Someone cheated on you. Or you cheated on someone. Or you've been close enough to infidelity — on either side — to feel its gravitational pull. And you've probably asked yourself the question that haunts these situations: is cheating a fundamental character defect, or is it something that happens when specific needs go unmet in a specific personality at a specific moment?
The answer isn't simple. And anyone who gives you a simple answer is selling you something. Let me walk you through what the research actually shows, what I've observed in my practice, and what it means for how we think about betrayal — both as the one betrayed and as the one who strayed.
The Uncomfortable Truth About Why People Cheat
Most people assume cheating is about sex. It's usually not. The most common reasons people give for infidelity, across study after study, are: emotional disconnection in the primary relationship, a sense of being unseen or unappreciated, a desire for novelty or excitement, and — this one surprises people — a desire to feel desirable again. To feel like someone who is wanted, not just someone who is tolerated.
Notice what's missing from that list: "because I'm a terrible person." Infidelity is rarely about character in the abstract. It's about specific needs colliding with specific opportunities under specific conditions of vulnerability. That doesn't excuse it. But it does explain it in a way that might be more useful than "they're just a bad person."
And here's the part that makes everyone uncomfortable: the personality traits that make someone more susceptible to infidelity are not inherently bad traits. High openness to experience — a trait we celebrate in artists, entrepreneurs, and innovators — is also one of the strongest predictors of infidelity. The same hunger for novelty that makes someone creative can make them restless in a long-term monogamous relationship. The trait itself isn't the problem. The context and the choices are.
How Specific Traits Increase Infidelity Risk
If someone is high in openness to experience, they need variety. New people, new situations, new dimensions of themselves to explore. In a long-term relationship, that need for novelty can either be met within the relationship — through shared adventure, through continued curiosity about each other, through a sex life that evolves — or it can be met outside it. The trait doesn't cause infidelity. But the trait unaddressed creates the conditions where infidelity becomes more tempting.
If someone is low in conscientiousness, they struggle with impulse control. They're more likely to act on attraction without fully processing the consequences. It's not that they don't care about their partner or their commitments. It's that the impulse arrives and the brake system that would stop them from acting on it is underdeveloped. Again: not an excuse. But an explanation that matters if you're trying to understand what happened.
If someone is low in agreeableness, they may simply be less constrained by concern for their partner's feelings. This is the closest the personality research gets to identifying a "character" component to infidelity. Low agreeableness correlates with lower empathy, less guilt about rule-breaking, and more willingness to prioritize one's own desires over others' wellbeing. This isn't about unmet needs. This is about a genuine limitation in the capacity to care about the harm one causes.
Pause and Reflect: If you've been cheated on, stop asking "wasn't I enough?" That question assumes the infidelity was about a deficiency in you. It almost certainly wasn't. The better question is: "what was going on in their internal world that made this seem like an acceptable choice?" Notice that this question is about them, not you. And if you cheated, ask yourself the same question — not to justify it, but to understand it well enough that you never repeat it.
The Difference Between a Mistake and a Pattern
A single instance of infidelity under specific, unusual circumstances — grief, intoxication, a relationship that was already dying — is meaningfully different from a pattern of repeated betrayals across multiple relationships. The first is a terrible decision. The second is a way of relating.
A mistake is situational. A pattern is structural. If someone cheated once, confessed, took responsibility, did the work to understand why they did it, and changed their behavior — that's a mistake. It doesn't mean their partner has to forgive them. But it does mean the cheating wasn't who they are. It was something they did.
If someone cheats in every relationship, minimizes it, blames their partners, and makes no effort to change — that's a pattern. That's not about unmet needs or specific circumstances. That's about a fundamental unwillingness to constrain their own desires for the sake of another person. And no amount of understanding or forgiveness from their partner will fix it, because the problem isn't in the relationship. It's in their relationship to commitment itself.
What This Means for Trust
If you've been betrayed, understanding the personality dynamics doesn't mean you have to forgive. It doesn't mean the betrayal was "understandable" in a way that obligates you to get over it. It means you get to stop asking the question that's been eating at you: "What did I do wrong?" You probably did nothing wrong. The infidelity was a solution to a problem that existed inside the other person — a problem they may not have even recognized they had.
If you're the one who cheated, understanding your own personality isn't an excuse. But it's the beginning of taking real responsibility. "I was just following my feelings" isn't responsibility. "I have high openness to experience, and instead of addressing that need within my relationship or being honest about it, I acted out destructively" — that's responsibility. That's the beginning of change.
Understanding the personality factors that contribute to infidelity — both the traits that make someone more vulnerable to it and the traits that protect against it — is part of understanding yourself and the people you love. The MyTraitsLab Personality Test helps you see those patterns clearly. Not to judge. Not to excuse. Just to understand. Because you can't change what you can't see.
