Why Do People Cheat? A Sex Therapist Has Some Fascinating Insight

Been cheated on? Turns out it really might be about them, not you. Health's new column, "Why Would Someone Do That?" explains.

Introducing Health's new column, But Why? Here, psych experts decipher the reasons behind the most puzzling human behavior mysteries.

Let me open with an assumption: If you’re reading the first few sentences of this article, chances are good that you’ve stumbled across it during a difficult period in your life. Sure, your Google search for “why do people cheat?” could have been completely academic in nature.

But if you’re anything like me, it probably came on the heels of a revelation that someone’s been unfaithful to you (or vice-versa), and your hunt for an answer was likely punctuated by more than one question mark. (No judgment.)

For me, being cheated on by my first boyfriend was more devastating than anything I’d felt in my life at the time. I was certain that our love would be forever, so when I walked in on him making out with some dude from work (who also had a boyfriend, so what gives, man?) I had no choice but to scream “see all of this time, I thought I had someone down for Whitney!,” rush out of his apartment, and spend the next two weeks trying to get our relationship back on track—which seemed like the most stoic and grown-up thing to do.

You can guess how that worked out by my searches during the next few months. It started with the fairly innocuous “Why’d he cheat??” moved into the more hopeful, “Can you come back from cheating?” Got very, very personal with “What the hell is so wrong with me that a guy who promised he’d love me always decided to have sex with someone who wears ugly sweaters instead???” and then became outright desperate: “What’s worse? A cheater or a dictator with the murder of thousands on his conscience?”

In my pain, I had decided that the man who cheated on me was evil, dark-hearted, a pox upon all the houses (not just those found in Verona). “What a bad person,” I thought, condemning him to a life of painful toil and misery.

Turns out my black and white view of infidelity wasn't the most honest way to look at it, sex therapist Vanessa Marin tells me. “We have a really black and white way of looking at infidelity, but it's important for us to see that there are a lot of shades of gray to it,” she says.

She understands the pain that cheating can cause, but she warns against generalizing those who have been unfaithful: “People who cheat, they're not terrible, evil, horrible people. There are plenty of really great, wonderful people who cheat as well. People do bad things. That doesn’t make them bad people," she says.

These people include Gloria, a 29-year-old woman who cheated on a partner who wouldn’t let their relationship end. “I had tried to break up with him several times and he kept telling me we should stay together,” Gloria says. “He also said I’d never find anyone better. I felt really trapped.”

When another man approached her, Gloria acted on her attraction. “I needed a release,” she recalls. “I told my partner right away and that really sealed the deal on our relationship ending.”

This kind of story is common—and often the easiest to swallow for people who renounce adultery of any kind. But Marin says that cheating is almost never this cut-and-dry. Though she often works with couples where one or both partners are sexually unsatisfied or not reasonably meeting their partners’ needs, these aren’t the only relationships in which she sees infidelity occur.

“We tend to think that people cheat because they’re unhappy in their relationships, and that certainly can be true, but the reality is more complicated," she explains. "It's important we recognize there are plenty of people in perfectly happy relationships who also cheat.”

Many people who cheat, Marin says, aren’t looking for something they’re missing in their relationship. Instead, the person cheating is dealing with issues in their relationship with themselves.

“They’re feeling lost in some way,” Marin continues. “Or they’re feeling disconnected with some part of themselves. And so they look for an affair to fill some missing gap, fill some hole, help them figure out something going on within themselves. There may not be an issue in their relationship with their partner at all.”

Some people, Marin says, aren’t actively looking to have an affair. Or they may not have ever considered they’d be open to the possibility. But then an opportunity presents itself—an out-of-town trip; someone new is attracted to them—and things happen without any pre-planning or malice aforethought.

Marin cautions that a lack of pre-planning doesn’t mean a lack of consequences. Cheating is not only a violation of trust, but also a betrayal of values. Whether a partner finds out about the cheating or not (some partners would even prefer not to know: “if my boyfriend has a one-night-stand, I don’t want to know about it,” one friend tells me) is immaterial. If you’ve made a commitment and violated it, Marin says, you’re going to have to sit with some very uncomfortable feelings.

“If monogamy, commitment, and trust are important values to you,” Marin says, “and you’ve done something massive to go against all those values, that’s a critical thing to address—whether you tell your partner about the infidelity or not.”

If you’ve been cheated on, Marin says, it doesn’t mean that there’s anything wrong with you. Though cheating often involves sex, it’s rarely about the sex itself. It’s more about having someone new providing attention. If the cheating partner has been in a relationship for a long period of time, it's about the excitement of an unexpected attraction.

“Infidelity is not a judgment or an indictment of the person who’s being cheated on," Marin says. "It’s not because they’re a bad person or not attractive or sexy. It's much more about what's going on with the person that cheated.”

Of course, Marin’s best advice for anyone who’s been hurt by their partner is to seek therapy to process their difficult feelings.

“You’re going to be devastated when it happens and that's okay,” says Marin. “You have to allow yourself to have those feelings and those reactions, because they make sense. But at some point you also have to recognize that it's much more about your partner than it is about you.”

Gloria says that cheating made her feel like the bad guy, a role she’d never expected to find herself in. That feeling is common, assures Marin, but also cautions against self-condemnation.

“Cheating is a very serious thing. It's a very big deal, and you should take the time to really sift through all of those feelings and reactions you're having," she advises. "At the same time, you also need to recognize that this doesn't make you a categorically terrible person. You are a good person who has done a bad thing. That’s a huge difference.”

Marin says that cheating offers an opportunity to learn an important lesson about yourself. The old adage “once a cheater, always a cheater” doesn’t hold up if someone who’s been unfaithful reflects on their actions, thinks about the impact these actions have had on others, and works to change how they approach relationships in the future—whether the cheating led to a breakup or not.

That’s been very true for Gloria, who recently celebrated her second anniversary with her boyfriend, a man she lives with and hopes to marry. “I learned to trust myself and be firmer with my decisions when it comes to relationships,” says Gloria. “I let someone talk me out of breaking up and then I made decisions that weren’t true to who I am as a person. That’s not something that’s going to happen again.”

I’m going to close with another assumption: If you’ve read this far, you’re probably curious about whether I was able to live, laugh, and love again after losing my ex to a dude who not only had a boyfriend but also wore ugly sweaters. The short answer is yes. The long answer is that it took a lot of work to build up the trust I needed to start dating again.

And though the man I thought I’d be with forever disappeared from my life as if he (and his DVD collection) had never been there, the relationship I grew with myself—through the work I did in therapy—helped me to recognize that being cheated on can feel like the end of the world, but it very rarely is.

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