Here's the uncomfortable takeaway, right up front: researchers who study cheating keep landing on the same finding — most affairs aren't one dramatic moment of weakness. They follow recognizable motives, and the people who learn those motives early are the ones who get to choose what happens next instead of finding out last. Since this piece first ran, one more pattern has earned its own entry: the whirlwind romance that was never romance at all — see pattern 7.
Start with the scale, because the numbers matter. The General Social Survey — the big American survey sociologists have run for decades — finds that among ever-married adults, about 20% of men and 13% of women say they've had sex with someone other than their spouse (the Institute for Family Studies' 2018 analysis of GSS data). Cheating isn't rare. It's common enough that understanding it is just practical.
The scenarios below are illustrative composites, not real people. The motives, though, come from published research — every study named and checkable at the bottom of this article.
What researchers actually found
For years the pop-culture story was simple: cheaters are either villains or victims of dead bedrooms. Then psychologists started asking cheaters directly why — and the answers were more complicated than the movies.
The most-cited modern study is Selterman, Garcia & Tsapelas (2019), published in The Journal of Sex Research: 495 people who admitted to cheating, surveyed about their motives. They didn't find one reason. They found eight distinct motives: anger, self-esteem, lack of love, low commitment, need for variety, neglect, sexual desire, and plain situational opportunity. Earlier work by Barta & Kiene (2005) had already flagged dissatisfaction, neglect, anger, and sexual desire — the 2019 study confirmed those and added the rest.
Two findings worth sitting with. First, the biggest driver overall was dissatisfaction with the primary relationship — the affair partner themselves mattered less than you'd expect. Second, attachment insecurity tracked with the anger, lack-of-love, and neglect motives: the people most afraid of being left were often the ones already halfway out the door. As couples therapist Esther Perel put it in The State of Affairs (2017), affairs are frequently less about the other person and more about what the affair represents — longing, lost parts of the self, a life unlived.
The six patterns below aren't armchair theory. Each one maps to motives the research actually measured. Learn the motive, and the pattern stops looking like a mystery.
The 6 patterns, mapped to the motives
1. The Slow Drift — motives: neglect, lack of love
Nobody plans this one. Two people get busy — work, kids, bills — and the relationship quietly becomes a logistics company. Emotional needs don't vanish; they just stop being met at home. Then someone at work asks "how are you, really?" — and listens. It's not a decision. It's a door left open, exactly the neglect motive Selterman et al. measured.
Red flag: they light up around someone else the way they used to light up around you, and one new "friend's" name keeps surfacing in every story.
2. The Novelty Chase — motives: need for variety, sexual desire
The one people understand least, because nothing has to be "wrong" for it to happen. Some people cheat for the newness itself — the thrill, the secrecy, the stranger who gets the fun version of them. The relationship can be perfectly fine. The itch isn't for something better; it's for something different. In the 2019 data, this motive clustered with an unrestricted attitude toward casual sex — a trait, not a phase.
Red flag: a history of short, intense flings that all "just fizzled out," and boredom treated like an emergency.
3. Revenge Cheating — motive: anger
Tit for tat, with heartbreak as the currency. One partner cheats — or is merely suspected of it — and the other decides the score needs settling. It's rarely about desire for the new person; it's about making the pain symmetrical. The research lists anger as a standalone motive, and it behaves like one: cold, deliberate, and aimed at the partner more than at pleasure.
Red flag: "after what YOU did" becomes a permanent trump card, and a pointed new interest appears right after a betrayal surfaces — timed like a press release.
4. The Exit Affair — motives: low commitment, lack of love
The relationship ended months ago; someone just hasn't moved out yet. The affair isn't what kills it — it's the landing pad. People line up the next thing before ending the current one because being alone for a minute feels worse than being dishonest for months. Low commitment, the researchers found, is its own motive: not "I fell," but "I was already gone."
Red flag: no plans, no "next year we should..." — just fog about the future, then a suspiciously fast someone-new after the split.
5. The Digital Double Life — motives: situational, sexual desire
A whole second relationship conducted through a glowing rectangle: secret accounts, deleted threads, a parallel life in a pocket. In person they're present — laughing at dinner, watching the show. The situational motive ("opportunity made it easy") thrives here, because the phone made cheating logistically effortless in a way no prior generation had.
Red flag: visible panic when you reach for their phone, apps that vanish and reappear, notifications swiped away mid-sentence. Privacy doesn't flinch; secrecy does.
6. The Slow Fade — motives: neglect, lack of love
No big fight, no dramatic exit — a dimmer switch turning down one notch at a time. Date nights get "rescheduled," texts get shorter. The effort doesn't disappear; it gets redistributed to someone else. If you bring it up, you're "imagining things" — even though your calendar and your gut agree something shifted.
Red flag: "so busy" lately, yet always free for one specific person. The warmth didn't vanish; it relocated.
7. The Love-Bomb-to-Cheat Pipeline — motives: low commitment, need for variety
This one starts before the relationship even settles. A whirlwind opening — grand gestures, constant contact, "I've never felt this way" by week two — and then, right when you'd expect things to deepen, the intensity drops and the wandering starts. It wasn't a romance that went wrong; it was a chase that ended the moment the chase was won. In the language of the research, this maps to low commitment and need-for-variety motives: the thrill was the novelty, not the person.
Red flag: the relationship had a highlight reel but no slow moments — fireworks at the start, fog by month three, and a new "exciting person" just as the routine began. If the opening act felt like too much, too fast, read love bombing vs genuine interest: 9 signs that tell them apart — the boundary test there settles it in one move.
The 60-second red-flag scan
- A phone that became a state secret overnight.
- Emotional energy clearly being spent somewhere else.
- Stories with plot holes — timelines that don't survive questions.
- A sudden glow-up with no occasion attached.
- The future going foggy: no plans, no dreams, no "we."
- You're "imagining things" every time you name what you see.
If several of these are hitting at once, read our 7 signs your partner might be cheating — and for the sheer absurdity of how these things surface, the 9 wildest ways cheaters got caught is uncomfortably educational.
What actually helps
Here's the grounded version, no preaching: knowing the motives doesn't give you control over someone else's choices. What the research implies is subtler. Affairs driven by neglect and dissatisfaction are the ones where the relationship may still have something to work with — if both people want to do the work. (Past the why and into the what-now? Our guide to whether you should stay after he cheated once walks through that decision honestly.) Affairs driven by chronic low commitment or novelty-seeking are information too: about compatibility, not your worth. Detective work — spyware, interrogations, phone forensics — appears in no study's recommendations. The boring answer that keeps showing up is honest conversation about unmet needs, early, before the drift becomes a decision. And if you're the one recognizing yourself in these patterns, naming the motive honestly is the first step that actually changes anything. (Related: is emotional cheating real cheating? — the debate that splits couples.)
Sources — check them yourself
- Institute for Family Studies (2018), "Who Cheats More? The Demographics of Infidelity in America" — analysis of General Social Survey data: ~20% of ever-married men, ~13% of ever-married women report infidelity.
- Selterman, D., Garcia, J. R., & Tsapelas, I. (2019). Motivations for extradyadic infidelity revisited. The Journal of Sex Research, 56(3), 273–286.
- Perel, E. (2017). The State of Affairs: Rethinking Infidelity. Harper.
- Barta, W. D., & Kiene, S. M. (2005). Motivations for infidelity among heterosexual individuals (as cited in Selterman et al., 2019).
