I'd also like to add....
That a simple "affair", (while it may be a big thing between old married "friends" and it might be a big deal between THEM); is nothing compared to what's really going on in Washington, the CIA or the Middle East! C'MON!!
I have known a few couples who make it that far, and an affair here and there never took apart the marriage. They looked the other way. Most don't even sleep in the same room. This smacks of something else. Petraeus is going down for SOMETHING ELSE.