Cheating can obviously be premeditated. But since it can also be one of those things that just "happens in the moment," it makes sense why a lack of impulse control might cause someone to jump at the chance without even thinking — should a sexy situation arise.

And that could be due to several different factors affecting the brain, and thus its ability to think before it leaps. "Sometimes people are more impulsive from a head injury or stroke," says Klapow. "And sometimes conditions have impulsivity as a symptom, such as ADHD. All of these individuals are more prone to make impulsive choices without planning and thinking. Thus the propensity to make a poor decision and fall to a passing impulse is there." Of course, head injuries, stroke, or ADHD don't necessarily predispose you to cheating. But it can, in some cases, make it more likely.

If someone grew up in a household where cheating was common, they might be wired to repeat the process themselves later on in life. "So much of our wiring happens during our formative years — our childhood," Klapow says. "If we grew up in a home where cheating was present, where we were taught that 'this is just what happens,' then we learn and we can possibly become wired to cheat." While it doesn't guarantee anything, if someone grew up in this type of environment, it might be difficult for some them to understand why cheating might be wrong.

This one might sound strange, but a study at Oxford University noted a link between longer ring fingers, testosterone levels, and cheating. So in theory, simply taking a peek at someone's hand might reveal a lot about their character.

According to the study, "The shorter the index finger in relation to the ring finger ... the higher the levels of testosterone that person is likely to have been exposed to while developing in the womb. This is true for both men and women."

And it's these higher testosterone levels in the womb that may make someone more likely to be unfaithful later in life. "From previous work, the researchers already knew that the higher levels of [fetal] testosterone can go together with greater sexual promiscuity as an adult," the study noted. "While not predictive of individual [behavior], the length of the ring finger versus the index finger can help identify the group of people who are more likely to be promiscuous." Say what?

While you can't peer into someone's head or measure their brain chemicals, studies have shown a connection between certain brain juices (or a lack there of) and cheating. Namely: oxytocin and vasopressin. According to a study published in Evolution and Human Behavior, having fewer receptors for oxytocin and vasopressin in the brain was linked with a higher likelihood of infidelity. Since these components are found to be essential in emotional bonding, it makes sense why having a shortage of these chemicals in the brain may affect fidelity.

As a result, research suggests that sex might be purely physical for people with less of these chemicals, instead of a bonding experience, like it is for many people who couple up and have long-term relationships. And that can make it difficult for them to stay faithful in a relationship.

While there's nothing wrong with watching porn, research suggests that some people who watch it often may be more likely to cheat. One study suggested "that seeing physically attractive and sexually available partners on screen may heighten a person’s perceptions of [their] own possible partners. And second, that porn may make the idea of multiple sexual partners more appealing," Peg Streep, author of Daughter Detox: Recovering from an Unloving Mother and Reclaiming Your Life, noted on Psychology Today.

And, according to Klapow, porn may create unrealistic expectations of what sex and intimacy is like, especially in the context of a relationship. "Watching porn in and of itself doesn't cause you to cheat," says Klapow. "However, to the extent that your expectations for what sex should be like are altered, how your partner should perform is influenced, and what is possible outside of your relationship is introduced — the risk for cheating goes up. Because there is so much porn and access is so easy, often people lose their grounding on what is the reality of a relationship versus the fantasy of a porn video."

Again, this isn't the case with everyone, and people who enjoy porn can still have healthy relationships and sex lives. But when the lines between what constitutes reality and fantasy are blurred, infidelity could be more possible.

A person can cheat, whether they have black hair, brown hair, blonde hair, red, pink — you name it. But one study showed that when it comes to infidelity, people with blonde hair are slightly more likely to cheat.

CheaterVille.com, a website documenting alleged cheaters, "conducted an internal study of online postings submitted by a cross sample of its users. Although still preliminary, the findings reveal ... evidence, which could indicate whether a partner is statistically likely to cheat, or there is a higher probability one might be the victim of cheating — all based on hair color."

The study revealed that 42 percent of identifying females posted as alleged cheaters had blonde hair, compared to 23 percent for red, 20 percent for brown, and 11 percent for black. And the people most likely to be cheated on? Those with brown hair, at 43 percent.

Keep in mind, the hair colors were self-reported, so it's unclear if this is natural hair color or dye we're talking about. Or why hair color might play a role at all. But it is something interesting to think about.

This is another one that sounds super strange. But yes, there is a connection between a higher IQ and the chance someone might cheat. As Bennett says, "One study showed that more intelligent individuals (as measured by IQ) are more likely to cheat on their partners."

Bennett believes it might have something to do with how those with higher IQs tend to bring in more income — and how that might open up their options in the dating pool. "So, someone with a higher IQ is also more likely to be considered a 'catch' by society's standards. That person would, by implication, have more opportunities and temptations to cheat."

From a psychological standpoint, experts say there may be a connection between people who fall into a pattern of serial cheating, and those who experienced early separation or abandonment by a mother or father. "Examples include divorce, a parent leaving and not returning, or an angry parent who rages toward the child unexpectedly and abusively (physically or verbally)," Dr. Fran Walfish, a Beverly Hills family and relationship psychotherapist, tells Bustle. Because of these difficulties during childhood, a possible fear of abandonment could make having healthy relationships difficult, which may lead to cheating.

Walfish also says some people cheat after sustained periods of mistreatment in a relationship. There are many reasons for this, but it could be due to neglect, which can cause a person to look for physical and emotional love elsewhere.

But despite how long someone's ring finger is, or how impulsive they might be, it doesn't mean cheating is a ever guaranteed to happen. At the end of the day, we all have control over what we do, as well as whether or not we want to be in a relationship. Speaking with a partner about what might be missing from your relationship is a great way to start. But if you find that you're the type who's interested in having more than one person in your life, than a monogamous situation might not be for you. And that's completely OK.