Money puts a major strain on relationships. Not only is a top predictor of divorce, but also a cause of infidelity, according to a new study in the American Sociological Review. 

The research found that people, namely men, are more likely to be unfaithful if their partners make more money in the relationship. Study author Christin L. Munsch came to this conclusion after looking at National Longitudinal Survey of Youth data of heterosexual, married couples ages 18-32 over the span of 10 years.

“From a rational perspective, we think, ‘Why would I bite the hand that feeds me?’” Munsch said in an extensive interview with Forbes. “But I think what this shows is, neither men nor women like inequality in their relationships… And when we compare ourselves to our partner, we don’t want to continually feel like a loser.”

HBO's "Girls" subtly addresses this phenomenon in season one, when free-spirited Jessa accepts a babysitting gig and develops an odd connection with the kids' unemployed, depressed (and married) dad. The rapport is innocent until he shows up to a party she's at and asks to sleep with her. She declines, which delivers a bigger blow to his self esteem. 

How infidelity allows men making less to reclaim their masculinity

Both men and women alike are at a higher chance of fooling around when their partners are more financially stable, but this is especially common among males. Munsch said men may feel emasculated when their wives are the household providers, and this can lead them to have affairs as a way to reclaim their masculinity. She adds that females who bring in more money will go out of their ways to massage their husbands' egos. 

“Infidelity allows threatened men to distance themselves from, and perhaps punish, their higher-earning spouses,” Munsch said in an interview with The Wall Street Journal.

Why male breadwinners are also big cheaters

Munsch said male breadwinners are also more likely to commit infidelity. Much like Don Draper in "Mad Men," men in power often have more opportunities to cheat.

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Men are most likely to cheat when their wives are fully financially dependent on them, as the wives may be less likely to file for divorce without incomes themselves, Munsch said.

"These men are aware that their wives are truly dependent and may think that, as a result, their wives will not leave them even if they cheat," Munsch said.

Munsch recommends tying the knot with someone who loves you regardless of your income and isn't drawn to dollar signs.

“That’s the type of person you would want to marry,” Munsch said. “Somebody who’s like, ‘I really don’t care that you’re making more money than me; I think it’s awesome’—they’re genuinely happy for your successes. And this’ll be for men or for women, because women also are at an increased likelihood [of cheating] when they make less money.”

She said the situation might also be different if someone is choosing to be a stay-at-home parent or work less versus earning less money by default.

Social media's impact on fidelity

Earlier this year, University of Missouri School of Journalism doctoral student Russell Clayton surveyed nearly 600 Twitter users and found that social media can also play a huge role in infidelity. According to Clayton's findings, active Twitter use "leads to greater amounts of Twitter-related conflict among romantic partners, which in turn leads to infidelity, breakup, and divorce." Clayton also found that the duration of a relationship doesn't impact how Twitter use is received in relationships.

“I found it interesting that active Twitter users experienced Twitter-related conflict and negative relationship outcomes regardless of length of romantic relationship,” Clayton said. “Couples who reported being in relatively new relationships experienced the same amount of conflict as those in longer relationships.”