"Like the 'tall, dark, and handsome' cliche, some women are attracted to men who possess the three qualities of wealth, celebrity, and influence," Dr. Terri Orbuch, director of a 25-year-long study on marriage and divorce funded by the National Institute of Health, told Yahoo! Shine in an interview. "From a purely biological perspective, for females success implies that the male will be a good provider and offer security. Of course, this makes little sense in the case of a married man, but it is nevertheless part of the underlying, unconscious appeal such men have to women."
Related: Do Some Careers Make Us More Likely To Cheat?
Emotional need may also play a role. In his autobiography, Clinton said that he cheated on his wife with Lewinsky "just because I could," but Lewinsky has said that she wasn't simply attracted to the former President.
"I fell in love," she told a grand jury in 1998. "We spent hours on the phone talking. It was emotional. We were very affectionate, even when—after he broke the relationship off in—maybe, I mean, when I'd go to visit with him, we'd—you know, we'd hug each other a lot. You know, he always used to like to stroke my hair. He—we'd hold hands. We'd smile a lot. We discussed a variety—you know, a wide range of things. So, I mean, it was—there was a real component of a relationship to it and I just—I thought he had a beautiful soul."
Rielle Hunter may have piqued former presidential hopeful John Edwards' interest by telling him, "You're hot!," but after the affair was over she told CNN's Piers Morgan that it was about love, not sex.
"I actually regret having an affair with a married man," she said in April. "I do. It's an awful thing. But I don't regret loving him."
"In a culture raised on Disney films, love may seem like the best justification of all," says Rick Reynolds of Affair Recovery. "Don't all cravings and desires need to be fulfilled? Far too often the consequences of infidelity are buried under the fantasy of falling in love."
There's a biological component as well. While a person can't "fall in love" at will to justify anything, Orbuch told Yahoo! Shine, "Levels of dopamine, norepinephrine, testosterone, phenylethylamine (PEA), and serotonin spike in the brain when we are experiencing romantic love. It's a potent cascade of love chemicals that influence our mood, rationality, and responses."
"In other words, when a woman has a mad crush on a man, she's probably not thinking too clearly. She's not thinking about the consequences—nor is he," Orbuch continued. "Once they've been bitten by the lust bug, they are like a fast-moving locomotive. A train wreck may be ahead (usually is), but they can't see it, or they choose not to."
Men in positions of power have plenty of opportunities to stray, and men in high-risk jobs—like politics and the military—may crave the adrenaline rush that comes with a new conquest. There are also plenty of opportunities for them to be unfaithful to their wives: Witness Arnold Schwarzenegger and his affair (and resulting love child) with his housekeeper, Patty Baena, or Eliot Spitzer, a.k.a. "Client-9," and the thousands of dollars he spent hiring prostitutes.
"The most common reason for an affair is high opportunity," psychologist Barry McCarthy told Psychology Today. "People fall into affairs rather than plan them."
But a 2011 study suggests that there's more to Petraeus' affair than that. According to researchers at Tillburg University in the Netherlands and Northwestern University in the U.S., both men and women in positions of power are more likely to think that societal rules don't apply to them—even if their power is temporary.
"The powerful engaged in more immoral behavior but found such behavior less acceptable," writes Joris Lammers, who co-authored the study. "The powerful judged their own moral transgressions more acceptable, but the same transgressions committed by others less acceptable compared to low-power participants." He calls this "Moral Hypocrisy" and, most people would agree, politicians and celebrities the world over have this in spades.
As a general, Petraeus, was lauded for his integrity and honor, but he was also used to having near-absolute authority and a high-stress, adrenaline-fueled job—a combination that made him a perfect candidate for an extramarital affair, especially given that Broadwell was 20 years his junior, attractive, and openly admired him.
Petraeus, 60, met Broadwell, 40, in 2006, when she was a doctoral student at Harvard University and he was a lieutenant general. The fact that he chose her to write his biography, "All In: The Education of General David Petraeus," in 2010 raised warning flags from the start.
"For him to allow the very first biography to be written about him to be written by someone who had never written a book before, seemed very odd to me," Peter Mansoor, who worked as an aide to the former general, told ABC News.
Broadwell had nearly free access to the general during the six trips she made to Afghanistan as his official biographer; the Washington Post reports that the married mother of two was treated "as though she were a member of Petraeus' inner circle and was afforded VIP housing in the main U.S.-NATO headquarters in Kabul"—a huge change from his "no reporters in my headquarters" stance in Iraq. Sources close to the general told ABC News that while in Afghanistan, Broadwell was embarrassingly "gushy" about Petraeus, and seemed to think she "was in love with him."
Their affair began after he retired from the Army in 2011, Petraeus says, and experts agree that a stressful transition or major life change can trigger infidelity. Petraeus' entire life has been defined by his military career, from his education at the U.S. Military Academy at West Point to his rise through the Army ranks; missing the military and the instant respect he commanded as a general could have made his relationship with Broadwell—who also graduated from West Point and is a lieutenant colonel in the Army Reserves—even more attractive, a chance to relive his glory days with someone who could relate to Army life and admire his many military achievements. For Broadwell, who had already spent years researching Petraeus' life, it would have been easy to revel in the attention of a war hero—something her non-military husband couldn't offer.
While it's unclear whether Petraeus has had any other extramarital relationships (or whether he shared classified information with Broadwell), critics say he's had plenty of practice at hiding things in plain sight—another hallmark of powerful people who know that their actions are unlikely to be questioned.
"More so than any other leading military figure, Petraeus' entire philosophy has been based on hiding the truth, on deception, on building a false image," Michael Hastings, who has covered Petraeus for seven years now, points out at Buzzfeed. " 'Perception' is key, he wrote in his 1987 Princeton dissertation: 'What policymakers believe to have taken place in any particular case is what matters—more than what actually occurred.' Yes, it's not what actually happens that matters—it's what you can convince the public it thinks happened."
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