What is Considered an Affair? Understanding the Boundaries of Betrayal

As a couples therapist in Blackheath, Southeast London, I often meet partners grappling with the aftermath of betrayal. Whether the infidelity was physical, emotional, or digital, understanding what constitutes an affair is the first step towards healing.

When couples arrive for therapy following an affair, one of the most striking dynamics I see is the disagreement over whether an affair has actually occurred. One partner feels devastated by what they perceive as a fundamental betrayal, whilst the other insists that "nothing really happened" or that their actions "don't count" as infidelity. This disconnect isn't simply about semantics or denial, but it reflects genuinely different understandings of what constitutes a violation of the relationship contract, and these differences can be as painful as the betrayal itself.

The question "what is an affair?" might seem straightforward, but in my work as a couples therapist in southeast London, I've found it to be one of the most complex and contentious issues that partnerships face. The answer depends not only on actions taken but on expectations set, agreements made (or assumed), and the unique emotional architecture of each relationship.

The Traditional Definition: Physical Infidelity

When most people think of affairs, they picture physical or sexual infidelity. This remains the most universally recognised form of betrayal: engaging in sexual activity with someone outside the committed relationship.

Physical affairs are often easier to define because there's a clear boundary crossing. However, even here, questions emerge. Does a drunken kiss constitute an affair? What about sexual activity that stops short of intercourse? Different couples draw these lines differently, and what feels permissible in one relationship may constitute a profound betrayal in another.

The impact of physical infidelity extends far beyond the acts themselves. Many individuals who've experienced this form of betrayal describe symptoms consistent with betrayal trauma: intrusive thoughts, hypervigilance, difficulty trusting, disrupted sleep, and a pervasive sense that their reality has been shattered. The experience often resembles grief, because there is a genuine grief for what the relationship was and for the trust that has been lost. The body keeps score of these violations, and healing requires more than simply ending the affair.

The Grey Area: Emotional Affairs

Emotional affairs represent one of the most contentious areas in modern relationships. An emotional affair involves forming a deep emotional connection with someone outside the relationship that rivals or supersedes the intimacy shared with one's partner. The person engaged in the emotional affair may insist "we're just friends" or "nothing physical happened," whilst their partner experiences a profound sense of abandonment and betrayal.

Characteristics of emotional affairs often include:

• Sharing intimate thoughts, feelings, and experiences with someone other than your partner

• Turning to this person for emotional support before turning to your partner

• Discussing relationship problems or frustrations with this person

• Feeling excitement, attraction, or anticipation about interactions with this person

• Keeping the depth or frequency of the relationship secret from your partner

• Comparing your partner unfavourably to this person

• Spending significant time thinking about this person

In couples therapy, I frequently encounter partners who feel blindsided when their emotional connection to someone else is labelled as an affair. They genuinely believed they'd maintained appropriate boundaries because no physical line was crossed. Meanwhile, their partner experiences a violation that feels every bit as devastating as sexual infidelity, sometimes more so because emotional intimacy is the foundation of their relationship.

The rise of emotional affairs reflects changing relationship dynamics. As we've moved away from marriages based primarily on economic partnership or social convention, emotional intimacy has become central to how we define successful relationships. When that intimacy is shared elsewhere, it strikes at the heart of what makes the partnership meaningful.

Digital Betrayal: Online Infidelity

Technology has created entirely new categories of behaviour that previous generations never needed to navigate. Online infidelity encompasses a broad spectrum of digital interactions that one or both partners may perceive as violations:

• Engaging in sexual conversations or sexting with others

• Sharing intimate photographs with people outside the relationship

• Maintaining profiles on dating apps whilst in a committed relationship

• Consuming pornography in ways that violate relationship agreements

• Developing intimate online relationships through social media or gaming platforms

• Engaging with webcam performers or paying for online sexual content

• Maintaining secret online personas or accounts

The debate around online infidelity often centres on whether virtual interactions "count" as real betrayal. One partner may argue that because there's no in-person contact, no affair has occurred. The other partner experiences genuine betrayal trauma, feeling that their trust has been violated and their relationship degraded.

Digital infidelity is particularly insidious because it's so accessible. The threshold for crossing boundaries is lower when it can be done from one's sofa whilst one's partner sleeps upstairs. The secrecy, the sexual or emotional energy directed elsewhere, and the deception all create wounds that therapy for infidelity must address.

Micro-Cheating: The Subtle Boundary Crossings

The term "micro-cheating" has entered our vocabulary to describe small actions that aren't quite affairs but that signal interest in someone outside the relationship or cross boundaries of appropriate behaviour. These might include:

• Maintaining active contact with ex-partners in ways that feel secretive or inappropriate

• Flirting with others in person or online

• Downplaying your relationship status when talking to attractive people

• Saving someone's contact under a false name to hide the connection

• Sharing inside jokes or frequent private communication with someone you're attracted to

• Repeatedly "liking" or engaging with someone's social media in ways that signal interest

Micro-cheating matters because it often represents the beginning of a gradual process of boundary erosion. What starts as seemingly harmless interactions such as a flirtatious message, an emotional connection kept secret, or a selective omission can slowly desensitise someone to the boundaries that once defined the relationship. Each small crossing makes the next one easier, until the line between what feels acceptable and what constitutes betrayal becomes blurred. More importantly, it reflects a willingness to deceive one’s partner, however minor the deception might seem.

The Anatomy of Betrayal: Why Affairs Hurt

Regardless of the specific definition, affairs share common elements that explain their devastating impact:

Deception: Perhaps more than the specific acts, the lying, hiding, and gaslighting that accompany affairs create trauma. The betrayed partner begins to question their own perceptions and judgement.

Exclusivity violation: Most committed relationships rest on some form of exclusivity agreement, whether sexual, emotional, or both. Affairs violate this foundation.

Priority displacement: Affairs signal that someone or something else has become more important than the primary relationship, at least temporarily.

Reality fracture: Discovery of an affair shatters the betrayed partner’s understanding of their life and relationship. They must reconstruct their reality whilst grieving the loss of what they thought they had.

Secondary losses: Along with losing trust in their partner, the betrayed individual often loses their sense of self, confidence, belief in their judgement, and sometimes their entire social world if friends knew about the affair.

Identity rupture: For many, betrayal destabilises their sense of who they are in relation to others. It can trigger existential questions about worth, loveability, and meaning, leaving the person feeling unanchored.

Betrayal trauma is increasingly recognised as a legitimate psychological injury with symptoms similar to post-traumatic stress disorder. The betrayed partner may experience flashbacks, intrusive images, panic attacks, depression, and difficulty functioning. The nervous system responds to relational betrayal as it does to other threats to survival, because for humans, social connection is survival. The attachment bond that once offered safety becomes a source of danger, confusing both mind and body.

Establishing Boundaries: The Relational Contract

Every relationship operates on a contract - a set of agreements about what the relationship is and how both partners will behave within it. Some of these agreements are explicit: "we're monogamous," "we're in an open relationship," "we've agreed not to contact ex-partners." Many more are implicit: assumptions about what fidelity means, what privacy looks like, what constitutes appropriate behaviour with others.

Affairs represent a breach of this contract. The devastation occurs not just because of the specific actions taken, but because the fundamental agreement that holds the relationship together has been violated. When couples disagree about whether an affair has occurred, they're often discovering that they never had the same contract to begin with.

The most functional couples I work with in therapy aren't necessarily those who never face temptation or attraction to others. They're the couples who have made their relational contract explicit. They've had honest conversations about boundaries and expectations before problems arise, and they've created space to renegotiate those boundaries as the relationship evolves.

This means discussing what exclusivity means in their specific relationship, what behaviours would constitute a betrayal, and how they'll navigate situations that test their agreements. It means understanding that boundaries aren't about control but about creating clarity and safety. It also means establishing a pattern of honesty where small concerns can be raised before they become large breaches of trust.

The goal isn't to create a rigid rulebook but to ensure both partners understand the terms of their relationship and have genuinely agreed to them. When both people are operating from the same contract, there's far less room for the kind of devastating misunderstandings that bring couples to therapy.

When the Damage Is Done: Moving Forward After Infidelity

When an affair comes to light, couples face several critical questions:

Can the relationship survive?

Not all relationships should or will survive infidelity. The answer depends on many factors: the nature of the affair, the willingness of both parties to do difficult work, the state of the relationship before the affair, and whether the fundamental dynamic that led to the affair can change.

Some relationships were already fragile or dysfunctional before the affair occurred. In these cases, the affair may be a symptom of deeper incompatibilities or patterns that cannot be resolved. Other relationships had a solid foundation that was damaged but not destroyed. The affair may have occurred during a period of stress, disconnection, or poor judgement rather than reflecting something fundamentally broken in the partnership.

The question of survival also depends on what both partners want. Some betrayed partners discover, through the pain of the affair, that they no longer wish to remain in the relationship. This is a recognition that trust, once broken, may not be worth rebuilding with this particular person. Conversely, some people who had affairs recognise that they want to leave the relationship, and the affair was an expression of that desire rather than something that can be worked through.

What does recovery require?

Healing from infidelity is possible, but it requires several elements: complete honesty from the person who had the affair, genuine remorse and accountability, understanding of why the affair happened, rebuilding of trust through consistent behaviour over time, and often the support of skilled therapy for infidelity.

Complete honesty means answering questions the betrayed partner needs answered, even when those questions are painful or repetitive. It means no more lies, not even small ones meant to protect the betrayed partner from further pain. Trickle truth - revealing information gradually rather than all at once - extends the trauma and makes recovery far more difficult.

Genuine remorse is different from shame or fear of consequences. Remorse involves understanding the impact of one's actions on the other person and genuinely wishing one had behaved differently. It means taking full responsibility without defensiveness or minimisation. The person who had the affair cannot tell their partner to "get over it" or complain that the betrayed partner is dwelling on the past. The injury was inflicted, and the person who caused it must allow the injured party to heal at their own pace.

Understanding why the affair happened is crucial for both partners. This doesn't mean making excuses - the person who had the affair is responsible for their choices. But understanding the circumstances, vulnerabilities, and relationship dynamics that created an opening for the affair helps both partners address the underlying issues. Was there emotional distance in the relationship? Unresolved conflict? A lack of honest communication about needs? Individual struggles with self-esteem or fear of intimacy? These factors don't justify the affair, but they do inform what needs to change.

Rebuilding trust happens through consistent, trustworthy behaviour over an extended period. This means being where you say you'll be, doing what you say you'll do, being transparent about your activities and communications, and demonstrating through actions that the relationship is now the priority. Trust cannot be demanded or rushed. It must be earned, and the earning takes as long as it takes.

How long will it take?

Recovery from betrayal trauma typically takes years, not months. However, the first three to six months are often the hardest. This timeline often shocks couples, particularly the person who had the affair. They may feel they've apologised, ended the affair, and are being trustworthy now - surely that should be enough?

But the betrayed partner's nervous system has been fundamentally disrupted. They've learned that their reality cannot be trusted, that the person they relied on most was deceiving them, and that their ability to perceive what's happening in their own life is compromised. These injuries don't heal quickly.

In my practice, I ask couples to commit to at least nine months of therapy before reviewing whether the relationship can continue. The first three months are usually the most intense, when both partners are acting very defensively and emotionally. The betrayed partner may be flooded with pain, rage, and intrusive thoughts. The person who had the affair may feel overwhelmed by guilt, defensive when questioned, or impatient with their partner's distress.

During these early months, therapy is aimed at holding the couple through this acute phase and helping them maintain communication so they don't destroy what possibility remains. The goal isn't to fix everything or make the pain disappear, but to prevent the couple from causing further damage whilst emotions are running so high. Once couples move beyond this initial crisis period, they can begin the next stage: making sense of the betrayal, understanding what happened and why, and exploring their place and feelings in the relationship.

The person who had the affair often wants to "move past it" long before the betrayed partner has healed. This mismatch in healing timelines can become another source of conflict. The person who had the affair may feel they're being punished indefinitely, whilst the betrayed partner feels they're being rushed to forgive and forget before they've properly processed what happened. Both experiences are understandable, and therapy for infidelity can help couples navigate this difficult terrain.

It's also common for the pain to resurface in waves. The betrayed partner may have weeks where they feel they're healing, followed by periods where the pain feels as acute as it did at discovery. Anniversaries, triggers, and new information can all restart the grieving process. This is the grief process at work. The betrayed partner is grieving the relationship they thought they had, the trust that's been lost, and the future they believed they were building together. Like all grief, it moves through stages - denial, anger, bargaining, depression, and eventually, for some, acceptance. These stages don't unfold neatly or in order. A person may cycle through anger and bargaining repeatedly, or find themselves back in denial months after they thought they'd accepted what happened. Understanding betrayal as grief helps both partners recognise that the intense emotional reactions aren't irrational or manipulative - they're the natural human response to profound loss.

What has been learned?

Whether the couple stays together or separates, the experience offers opportunities for growth: greater self-awareness, clearer boundaries, more honest communication, and deeper understanding of one's needs and values in relationships.

The betrayed partner often emerges with a clearer sense of what they will and won't tolerate, what they need in a relationship, and their own capacity for resilience. They may develop better skills for trusting their instincts and setting boundaries. Some discover strengths they didn't know they had.

The person who had the affair, if they genuinely engage with the work, may gain insight into their patterns of avoiding difficult conversations, escaping emotional discomfort, or seeking external validation rather than addressing internal issues. They may learn to communicate needs rather than acting on them secretly, to tolerate discomfort in relationships rather than fleeing, and to take responsibility for their choices.

For couples who stay together and do the work, the relationship may eventually become more honest and intimate than it was before the affair. They often develop a clear, explicit contracting of the relationship - openly agreeing to the terms of their partnership rather than operating on assumptions. This doesn't mean the affair was "worth it" or "for the best" - the same growth could have happened without the devastation. But the crisis can become a catalyst for change that both partners had been avoiding.

The Role of Professional Support

Working through the aftermath of an affair without support is extraordinarily difficult. Emotions run high, communication breaks down, and couples often find themselves locked in painful cycles of blame, defence, and withdrawal. Each partner experiences the situation from their own perspective, and these perspectives often feel incompatible. The betrayed partner needs to express their pain and have it witnessed. The person who had the affair feels overwhelmed by their partner's distress and may become defensive or shut down. Without a third party to hold the space, these conversations can quickly become destructive rather than healing.

Therapy for infidelity provides a structured container where both partners can be heard without the conversation spiralling into attack and defence. The therapist's role is not to take sides or to judge who was right or wrong, but to help both individuals articulate their experience and to facilitate understanding between them. This is harder than it sounds. When someone is in acute pain, they often struggle to hear anything that doesn't directly address that pain. When someone feels accused, they instinctively protect themselves rather than remaining open. The therapist helps navigate these dynamics, slowing down conversations when they become too heated, pointing out patterns that keep the couple stuck, and creating moments where genuine connection becomes possible again.

One of the most important tasks in therapy is creating safety for honest conversations. The betrayed partner needs to be able to ask difficult questions and express their pain without being shut down or met with defensiveness. The person who had the affair needs to be able to speak about what led to their choices without being met with such rage that honesty becomes impossible. These are delicate balances that couples struggle to achieve on their own, especially in the early months when emotions are most raw.

Therapy also provides space for understanding the factors that contributed to the affair. This is different from making excuses - the person who had the affair is responsible for their choices. But affairs rarely happen in a vacuum. There may have been patterns of disconnection, unmet needs that were never voiced, conflict that was avoided rather than addressed, or individual vulnerabilities that created openings for betrayal. Understanding these factors doesn't absolve anyone of responsibility, but it does help both partners see the fuller picture of how the relationship reached this point.

Processing the trauma and grief of the betrayed partner is central to the therapeutic work. The betrayed partner needs their experience validated - not minimised, not rushed, not compared to the struggles of the person who had the affair. They need space to express the full weight of their pain, their rage, their loss, and their confusion. They also need help understanding that what they're experiencing is a form of trauma and grief, not an overreaction or weakness. The therapist helps them make sense of symptoms that can feel overwhelming: the intrusive thoughts, the hypervigilance, the waves of emotion that seem to come from nowhere.

The question of whether and how trust can be rebuilt is one that therapy helps couples examine with clear eyes. Trust isn't rebuilt through apologies or promises. It's rebuilt through consistent, trustworthy behaviour over time, and through the person who had the affair demonstrating that they understand the impact of their actions. The therapist helps couples navigate what rebuilding actually requires: transparency, accountability, patience with the betrayed partner's need for reassurance, and the willingness to earn back what was lost rather than demanding it be freely given.

Therapy also helps couples develop new patterns of communication and intimacy. Often, the patterns that existed before the affair - avoiding difficult conversations, not expressing needs directly, withdrawing when hurt rather than addressing issues - contributed to the vulnerability that allowed the affair to happen. If the couple is to move forward, these patterns must change. This means learning to communicate more honestly, to express needs and boundaries clearly, to navigate conflict without contempt or stonewalling, and to rebuild emotional and physical intimacy in ways that feel safe for both partners.

Perhaps most importantly, therapy helps couples make informed decisions about the relationship's future. Not all relationships should survive infidelity. Sometimes, the affair reveals fundamental incompatibilities or patterns that cannot change. Sometimes, the betrayed partner discovers through therapy that they no longer want to remain in the relationship, and that's a valid choice. Sometimes, the person who had the affair recognises that they want to leave. Therapy provides space to explore these questions honestly rather than making decisions from a place of panic, guilt, or pressure.

Professional support also helps differentiate between normal difficulties in healing and situations where the relationship has become harmful or where recovery isn't possible. If the person who had the affair continues lying, shows no genuine remorse, or refuses to take accountability, the therapist can help the betrayed partner see this clearly rather than continuing to hope things will change. If the betrayed partner becomes abusive in their pain - something that can happen when trauma responses go unchecked - the therapist can address this directly. If both partners are simply going through the motions without genuine investment in repair, therapy can help them recognise this and make decisions accordingly.

Conclusion: Beyond Simple Definitions

The question "what is considered an affair?" has no single answer. It depends on the expectations, agreements, and vulnerabilities within each unique relationship. However, one consistent element often emerges: secrecy. If someone is hiding their behaviour from their partner, that concealment itself signals they know it violates the relationship agreement, even if that agreement was never explicitly stated. The presence of deception is often what transforms behaviour from a boundary discussion into betrayal.

What matters more than universal definitions is that both partners feel heard, that their experience is validated, and that the couple can work towards shared understanding. An affair represents a crisis of trust, honesty, and intimacy. Whether that crisis involves physical contact, emotional connection, digital interaction, or seemingly small boundary crossings depends less on external categories and more on what it means within the specific relationship. The pain is real regardless of the label, and healing requires acknowledging that pain whilst doing the difficult work of understanding how the betrayal occurred and whether trust can be restored.

For couples navigating this territory, the path forward requires courage, honesty, and often professional guidance. The goal isn't simply to return to how things were before but to build something more authentic, with clearer communication, genuine intimacy, and mutual respect for each person's emotional safety and wellbeing.

If you’re navigating the aftermath of infidelity or struggling with questions about trust and boundaries, couples therapy can help you find clarity and healing.

Book a consultation or learn more about therapy for infidelity in Blackheath and online.