Newt Gingrich was unfaithful to a brace of exes before he entered a third marriage swearing fidelity with a resolve as stiffened as wife Calista’s coif. His rationale for past behavior? “There’s no question at times of my life, partially driven by how passionately I felt about this country, that I worked far too hard and things happened in my life that were not appropriate,” he told The Christian Broadcasting Network last year.  Nothing gets a guy hornier than those late nights hammering out a soybean subsidy bill.

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Woody Allen never wed Mia Farrrow, but spent 12 years with the actress and her famously large brood, including a daughter, Soon-Yi, whom she had adopted with her former husband, composer-conductor Andre Previn. Farrow adopted two more children during her years with Allen, and the couple also had a biological son. Then Farrow discovered nude photos her lover had taken of Soon-Yi, then 20. Shame? Remorse? “The heart wants what it wants,” said Allen. No word on the wish lists of other organs.

Oscar Wilde left his wife at home with their two sons while he was out doing the Wilde thing with Lord Alfred Douglas. Instead of waxing witty about his man-izing, he used subjectivity as an esoteric defense: “Infidelity is an exhaustive subject that always falls short of words,” said Wilde, who died in 1900. “And whether it is acceptable or not, depends on the perception of an individual.”

Tiger Woods was playing a round, then playing around. The serial cheater, who entered rehab for an alleged sexual addiction, explained his infidelity to wife Elin Nordegren at a press conference: "I knew my actions were wrong. But I convinced myself that normal rules didn't apply…I felt that I had worked hard my entire life and deserved to enjoy all the temptations around me. I felt I was entitled… I was wrong. I was foolish. I don't get to play by different rules.” Penalty strokes ensued.

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Caught cavorting with a prostitute, disgraced New York Governor Eliot Spitzer told a reporter, "You gotta say this was an act of stupid hubris." More interesting was the assessment of Rutgers anthropologist Helen Fisher. In a segment of Today, she noted that the mess was his own doing, but added, "All you have to do is look at Eliot Spitzer. He has a high cheekbone and low brow ridges. Those are signs of very high testosterone."

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