Shocked, I tell you, shocked!
Perhaps the most surprising thing to emerge from the Petraeus scandal is that people are so surprised about it. True, Petraeus looks like a straight arrow and his military bearing is not one that brings to mind the image of a "lounge lizard." But he is a guy, and newsflash, guys to tend to act like guys when given the opportunity.
To the best of my knowledge, I've known two CIA guys (neither admitted it to me), and both were prolific womanizers. When your life is all about skullduggery, would you draw the line at an illicit affair? And why would it be any different at the top?
My guess, if everybody in the federal government who had some sort of illicit sex had to resign, we'd have to hold elections again, next week. And most of Congress, as well as the Executive branch, would be up for grabs.