Why people cheat (and what the reason can't tell you)

You keep asking the same question, and it never gets an answer that sticks.

Why would they do this?

You ask it in the shower. You ask it in the car. You ask it at 2am when the house is quiet and your mind starts building courtroom arguments.

Maybe you're asking because you found out. Or maybe you're asking because something has felt off for weeks and you're trying to understand how people even get here.

Most advice about why people cheat falls into two camps. It's always about something missing at home. Or they're just a bad person.

Both are tidy. Neither survives contact with the research.

The reason someone cheats isn't a verdict on your worth, and it isn't proof of anything about your relationship. It's a pattern worth understanding so you can stop using it to punish yourself.

Below: the eight motives researchers found, how an affair usually builds step by step, why the reason matters less than what happens next, and a short plan for using the answer instead of drowning in it.

People cheat for at least eight different reasons

If you want the direct answer to why people cheat, start here.

A research team led by Dylan Selterman at the University of Maryland surveyed 495 adults who admitted to being unfaithful in a committed relationship. After analyzing responses to a set of nearly 80 questions, they identified eight motives, published in the Journal of Sex Research (University of Maryland).

1. Anger – Often revenge for a partner's betrayal or hurt.
2. Sexual desire – Feeling unsatisfied with the sex in a relationship and wanting something new.
3. Lack of love – Loss of passion or interest in a partner, falling out of love.
4. Neglect – Not receiving enough love, respect or attention.
5. Low commitment – One partner is less committed than the other, or the two never agreed the relationship was exclusive.
6. Situation – Circumstances outside a person's normal life, such as being intoxicated, on vacation or under high stress.
7. Esteem – Trying to raise self-worth or feel independent.
8. Variety – Wanting to experience sex with many partners.

Read that list slowly.

Some of those motives point at the relationship. Some point at the person. One points at a Tuesday night, a bar and too many drinks.

That mix is the real finding. One affair can come from a slow drift between two people who stopped talking. Another can come from someone who was never fully committed. Another can come from a bad week and a bad decision.

The researchers also found group-level differences. Men were more likely to report sexual desire, variety and situational forces. Women were more likely to report neglect. That's a pattern in one sample, not a rule about your partner. The study's lead author noted that the sample leaned toward younger adults in dating relationships, so be careful stretching it to every marriage.

If you want the version of this written specifically for men, our posts on why guys cheat and 10 reasons why men cheat go deeper, and do men or women cheat more looks at how much of the gap is real.

The reason isn't always about the relationship, and sometimes it is

"But shouldn't there be something wrong with the relationship?"

That's the sentence people reach for, because it makes the world feel safer. If cheating only happens in broken relationships, then yours is safe as long as you keep it unbroken.

Selterman pushed back on that idea. We often hear that infidelity is a symptom of a damaged relationship, he said, but the research suggests it isn't that simple, and many motives aren't a direct reflection of a relationship's health (University of Maryland).

That cuts both ways.

It means you probably didn't cause it by being too much, too little, too tired or too busy. Relationships have problems. Most people with relationship problems don't cheat.

It also means a good relationship doesn't make anyone immune. That's a hard thing to hear, and it's also freeing. You can stop auditing every dinner from three years ago for the clue you missed.

Call this The Cause Fallacy: the belief that every betrayal must have a cause large enough to match the damage. The damage is huge. The cause can be small, selfish or situational. Pain doesn't scale with reason.

Many affairs start as a slow drift, not a single decision

Now the other half.

Sometimes the relationship was part of the story. The question is how.

The Gottman Institute describes an affair as the end of a cascade of steps that culminates in a transgression, a model they credit to John Gottman with Caryl Rusbult and Shirley Glass. It starts with the bid for attention (The Gottman Institute).

A bid is small. "Want to plan the weekend?" "Look at this." "Can we talk?"

When it's met with silence or irritation, the person who made the bid feels rejected. The Institute lays out how repeated failed bids can lead to negativity and avoidance, then to investing less and comparing more, then to feeling less dependent on the partner, and eventually to resentment, loneliness and idealizing alternatives.

None of that excuses the choice at the end.

The cascade describes how a person might get lonely enough to make a bad decision. It doesn't say they had to make it. They could have said I'm lonely, asked for counseling, or left.

If you're reading this because you suspect something and not because you found proof, this is also the most useful part. The slow drift tends to leave marks well before anything else does: conversations that get shorter, bids that get ignored, one person becoming oddly guarded. Our guide to the signs of cheating covers those patterns, and emotional cheating covers the version that begins long before anything physical.

None of it proves anything. A sign is a reason to look closer, not a verdict.

Three kinds of explanations you'll hear (and what each leaves out)

When people ask why someone cheated, they usually get one of three stories.

The Relationship story – You two stopped connecting. It's true often enough to be believed. It leaves out the fact that the person could have said so before acting.

The Character story – They're selfish, entitled, a liar. It's satisfying. It leaves out that the same person can be kind, loyal in other ways, and deeply ashamed.

The Moment story – It was a bad night, a trip, too much alcohol. It's the research's situational motive, and it's the easiest one to use as an excuse. It leaves out that the person chose to repeat, hide or lie about it.

Most real cases mix all three, in proportions nobody can measure from the outside.

So you can drop the question you can't answer ("what is the single true reason?") and ask the ones you can:

• Are they taking responsibility, or explaining why it was understandable?
• Has the outside connection actually ended?
• Will they answer the questions that affect your decisions?

Those three tell you far more than the motive does.

If you're the one asking why you did it

Some people land on this page from the other side.

Maybe you cheated. Maybe you're close to it. Maybe you're lying awake with a message you haven't sent and a feeling you can't name.

This site won't help anyone hide an affair, and it won't pretend the choice was out of your hands. But the motive list is a decent mirror, and it's worth using honestly.

Which of the eight is closest? Anger at a partner you haven't told. Neglect you've never put into words. Low commitment you never admitted. A situation you keep walking into on purpose. A need for esteem that a new person feeds for a while and then stops feeding.

Each of those has a name for a reason. A named problem can be talked about, with a partner or with a therapist, before it turns into a secret that has its own momentum.

Secrecy is what makes everything worse. It adds a second betrayal, the lying, on top of the first. If you want to stop, or you want to tell the truth, an individual therapist is a far safer place to start than a friend who'll take sides or a partner who'll hear it from someone else.

You don't have to be a villain to take responsibility. You just have to stop explaining and start repairing.

What to do with the reason once you have it

So what do you actually do with all this?

Here's a short plan. Call it The Three-Question Rule: you get to ask the why a few times, in a calm setting, and then the work moves to what happens next.

Step 1 – Ask once, in daylight. Pick a time that isn't midnight or mid-argument. Ask, "Help me understand how this happened." Listen for ownership, not polish.

Step 2 – Write down what you heard. Not to build a case. To stop the answer from changing in your memory at 3am.

Step 3 – Check it against behavior. A good explanation without changed behavior is just a story. Look for ended contact, honest answers and patience with your hard days.

Step 4 – Take the rest to a professional. The part you can't solve alone, the "why wasn't I enough" part, belongs in a therapist's office. Couples therapy can help if both of you are willing. Individual therapy helps if only you are. Our guide to therapy for a cheating spouse covers how to choose.

Step 5 – Decide later. The Gottman Institute describes its trust revival approach in three phases (atone, attune and attach) and notes there is no specific time frame for the process (The Gottman Institute). In practice that means you don't have to decide in week one whether to stay.

If you're past the discovery and need the next steps, how to get over being cheated on and how to rebuild trust in a relationship pick up where this leaves off.

And if you're not sure anything has happened, the free relationship assessment can help you separate real changes from fear. It shows patterns. It can't prove anything.

If any part of your situation involves threats, control or feeling afraid, contact the National Domestic Violence Hotline at 1-800-799-7233 or thehotline.org first.

The better question was never why

Here's what tends to happen.

You get a reason. It doesn't help. You get another. That one doesn't either.

That's because the why was never the real question. The real question underneath it is Was any of it real? and then Can I trust my own judgment again?

The reason someone cheated is a fact about them. What you do next is a fact about you.

You can understand a person without excusing them. You can forgive without forgetting. You can leave without a perfect explanation.

The answer you need isn't in their motive. It's in what you decide you're worth.

If you want to look at your own situation clearly, take the relationship assessment and see the pattern instead of the panic.

Sources

• Why do people cheat? UMD research identifies 8 motivating factors, University of Maryland College of Behavioral and Social Sciences
• How do affairs happen?, The Gottman Institute
• Reviving trust after an affair, The Gottman Institute
• National Domestic Violence Hotline