In other research, McNulty found that those who forgave partners who habitually behaved badly tended to feel worse over time. Forgiving people who did bad stuff, he concluded, didn't necessarily improve their behavior.
Indeed, we seem to hold politicians by a looser standard than people we actually know intimately, such as our own spouses.
A 2008 Gallup poll found that 64 percent of Americans wouldn't be able to forgive their husbands or wives for infidelity, compared to 33 percent who would. Interestingly, though, only 36 percent of Americans say that if they were married to an elected official, they would stand next to the person on a podium while he or she was answering questions about an affair, as Weiner's wife Huma Abedin did on Tuesday.
One reason why politicians have a chance to survive sex scandals is that Americans don't seem to consider them as serious as other sorts of misdeeds, and often draw a distinction between private morality and public conduct.
A 2011 scientific survey conducted by the Public Religion Research Institute, for example, found that 87 percent of Americans think elected officials who took bribes should resign, while only 55 percent say that those caught patronizing prostitutes should quit. And 44 percent of Americans believe that a politician who commits an immoral act in private life can still behave ethically in office, exactly the same number as those who think that a marital cheater can't be trusted with their tax dollars.