Having an Affair: What It Really Means, the Types, and What to Do Next

You are not reading this article because you are bored.

You are here because something shifted. Maybe it was the way they angled their phone away from you last Tuesday. Maybe it was the new cologne, or the sudden interest in going to the gym at 9 PM, or the way they said "just a friend from work" a little too quickly.

You typed "having an affair" into a search bar not because you want to know the dictionary definition. You want someone to tell you whether what you are feeling is real.

So let's talk about what affairs actually are — not the Hollywood version, not the moral lecture, but the real, research-backed anatomy of what happens when a partner steps outside a relationship.

What Actually Counts as Having an Affair

Here is the thing nobody tells you: affairs are not a single thing. They come in very different shapes, and each one does different damage.

Researcher Shirley Glass, whose book Not "Just Friends" reshaped how therapists understand infidelity, found that most affairs begin not with a kiss but with a conversation. Two people start sharing things they do not share with their partners. A wall goes up around the new relationship, and a window closes on the old one.

That is the core of it. An affair is not just about sex. It is about secrecy, emotional investment, and the redirection of intimacy away from your primary relationship.

Here are the main types:

That last one — the exit affair — is more common than people think. One study found that 40% of divorced individuals reported their marriage ended because one spouse left for a new partner. The affair was not the problem. The affair was the solution they chose instead of having the hard conversation.

You might be reading this and thinking: but they said it was nothing. They said I was overreacting.

That thought you just had? It is worth paying attention to.

If you are trying to figure out whether what your partner is doing qualifies as emotional cheating, the answer usually lives in the secrecy, not the sex.

How Affairs Actually Start (It Is Never How You Think)

Nobody wakes up one morning and decides to have an affair. That is maybe the most important thing to understand.

Therapist Esther Perel, who has spent decades studying infidelity, puts it this way: sometimes when people stray, they are not looking for another person — they are looking for another version of themselves. The affair is less about the partner they are cheating with and more about who they get to be in that other person's eyes.

That does not make it okay. But it matters, because it changes what you are actually dealing with.

Here is the typical pattern, based on Glass's research:

Stage 1: The friendship. It starts innocently. A coworker, an old friend who resurfaces on social media, someone at the gym. The conversations feel easy. There is no agenda.

Stage 2: The emotional crossing. They start sharing things with this person that they used to share with you. Frustrations about work. Fears about life. The stuff that used to be yours. Research shows that 53% of people who reported extramarital involvement said the other person was a close friend.

Stage 3: The secrecy. This is the hinge point. They stop mentioning this person. Or they mention them too casually, like they have rehearsed it. They delete messages. They get protective about their phone.

Stage 4: The rationalization. "We are just friends." "Nothing has happened." "You are being paranoid." By this point, even if nothing physical has occurred, the emotional architecture of an affair is already built.

If that progression sounds familiar, you might want to read about the 7 stages of emotional affairs — the pattern is remarkably consistent.

You know what that feeling is, right? The one where you are standing in your own kitchen and something feels slightly off, like the furniture got moved an inch while you were at work.

That instinct is not nothing.

The Patterns That Give It Away

Let's be honest about why you are really here. You want to know if the signs you are seeing are real.

Research from the Institute for Family Studies and other sources consistently points to a cluster of behavioral changes that tend to show up when someone is having an affair:

Changes in routine. New habits that appeared out of nowhere — suddenly working late, new fitness routines, unexplained errands. Not because these things are inherently suspicious, but because they represent a break from the established pattern of your life together.

Phone behavior. This is the big one in the digital age. The phone that used to sit face-up on the counter now lives in their pocket. New passwords. Notifications turned off. If you want to understand the full spectrum, we have written about micro cheating examples that often serve as early warning signs.

Emotional withdrawal. They are physically present but mentally somewhere else. Conversations become transactional. You used to talk about your days. Now they just ask what is for dinner.

Sudden niceness or guilt behavior. Sometimes the tell is not distance — it is unexpected gifts, compliments, or affection that feels performative. Like they are compensating.

Defensiveness. You ask a simple question — "Who were you texting?" — and the response is disproportionate. Anger. Accusations that you are controlling. The question becomes the problem instead of the answer.

Here is what 20 years of General Social Survey data tells us: approximately 20% of married men and 13% of married women admit to having had sex outside their marriage. When you expand the definition to include emotional affairs and intimacy short of intercourse, those numbers climb to roughly 45% of men and 35% of women.

You are not imagining things just because the odds are not 100%.

If you are seeing multiple patterns from this list, taking our relationship assessment can help you organize what you are noticing into something clearer.

What the Research Says About Who Has Affairs and Why

This is where it gets uncomfortable, because the research does not support the simple story we tell ourselves — that only bad people in bad relationships cheat.

According to data from the Institute for Family Studies, infidelity rates vary significantly by age, gender, and other demographic factors. Among young adults ages 18-29, women actually cheat slightly more than men (11% vs. 10%). The gender gap widens in older age groups.

A 2020 study published in the Journal of Sex Research identified eight key motivations for infidelity: anger, low self-esteem, lack of love, low commitment, need for variety, neglect, sexual desire, and situational factors.

Notice what is not on that list: "because they are a terrible person."

Perel makes the point that she regularly works with people who love their partners, who have been faithful for years or decades, and who are genuinely confused about how they got here. The affair is not always a reflection of the relationship. Sometimes it is a reflection of an internal crisis — a midlife reckoning, a loss of identity, a confrontation with mortality.

That does not make it hurt less. But understanding the why matters if you are going to figure out what to do next.

For a deeper look at the gender dynamics, our analysis of whether men or women cheat more breaks down the research in detail.

You might be sitting here thinking: but we were happy. At least I thought we were.

You might have been. That is the brutal part.

What to Do If You Think Your Partner Is Having an Affair

First: breathe. What you do in the next few weeks matters more than what you do in the next few hours.

Do not go through their phone. I know. You want to. But surveillance erodes your own integrity and rarely gives you the clean answer you think it will. What you find will either confirm your fears (and you will wish you did not see the details) or show nothing (and you still will not feel better, because absence of evidence is not evidence of absence).

Name what you are feeling, not what you are accusing. There is a difference between "I think you are cheating" and "I have been feeling disconnected from you, and I need us to talk about it." The first one triggers defense. The second one opens a door.

Get professional support before you confront. A therapist — even just for you, individually — can help you figure out what you actually want before you blow the situation open. Couples therapy for trust issues is one of the most effective paths forward. This is not weakness. This is strategy. Knowing what your boundaries are before the conversation starts is the single most important thing you can do.

If the patterns you are seeing align with the signs of a toxic relationship, the conversation you need to have might be bigger than just the affair.

Trust your gut, but verify with clarity. Your instincts brought you here. They deserve respect. But they also deserve the structure of a clear-eyed assessment rather than a spiral of late-night Googling.

That is exactly what our relationship risk assessment is designed for — not to catch anyone, but to help you see the patterns clearly and decide what to do with the information.

The Hardest Part Is Not the Knowing

The hardest part of suspecting your partner is having an affair is not the suspicion itself. It is the loneliness of it. The feeling that you cannot talk to anyone about it because saying it out loud makes it real.

But here is what the research consistently shows: couples who address infidelity with professional help have significantly better outcomes — whether that means rebuilding the relationship or ending it with clarity and dignity.

Having an affair does not automatically mean your relationship is over. And suspecting one does not make you paranoid.

It makes you someone who is paying attention.

Whatever you decide to do next, do it from a place of information, not fear. Get clear on what you are actually seeing. Talk to a professional. And know that wanting answers is not the same as wanting to be right.