Extramarital affairs probably reflect more on the  neurochemistry of love and chance circumstances than on someone's character.  People who fall in love/lust lose a lot of their ability to make "good" decisions (being faithful) because instinct is overriding social conventions.  Evolutionarily speaking, and instinctually, it is "good" for a male to have as many children as possible with as many females as possible.  I bet a lot of those with "good character" (faithful) simply haven't fallen into the circumstances that would cause them to compromise their character.  Being a politician or a celebrity tend to give you many more opportunities to do so. 

Humans are not naturally evolved to be purely monogamous.  By insisting on monogamy, we go against our true nature.

"Vasopressin is the monogamy chemical. Only about three percent of mammals are monogamous; mating and bonding with one partner for life. Unfortunately, humans are not one of these naturally monogamous animals. The prairie vole is however and it is this furry friend which is responsible for our knowledge about vasopressin." 

I like the European way better, but doubt there will be change anytime soon.  I think Americans delight in seeing politicians fall from grace.

still, its not as if the media is purely at fault. Look at this quote from John Edwards (courtesy of Andrew Sullivan):

"I think this President has shown a remarkable disrespect for his office, for the moral dimensions of leadership, for his friends, for his wife, for his precious daughter. It is breathtaking to me the level to which that disrespect has risen," - John Edwards, on Bill Clinton, 1999.

By accepting media and right wing narratives Democrats have legitimized and enabled the coarsening of public life. There's plenty of blame to go around.

with the crowd here and let me give you examples.

If you decide to become a career criminal you enter "the life". You do this knowing that risk winding up in prison or murdered if you slip up or for no particular reason. That is what you chose. Don't give me this liberal "all career criminals were forced into "the life" because of their economic and social hardships" line. It is true for some but I can personally guarantee you it is not true for all.

If you decide to try to be an entertainment star of some type, you know that if you succeed to will be entering "the life". If you are successful you will need to become some sort of recluse or have cameras aimed at you constantly and will constantly be watched. It is part of the deal and part of entering "the life".

If you decide to become a politician then once again you choose to enter "the life" and one of the biggest rules is no philandering. Some politicians do it and come away unscathed, some it actually helps their numbers but with most it destroys their career. Biology is not an excuse and that is the way it is and they know it when they choose to enter "the life".

Please don't give me the "in Europe" line either because when you do you sound the Texas Ding Dong Express who posts here talking about nuclear power plants in France . Culture, world view and the way things are done are just different on the other side of the pond.

That is the way it is.