Bunch of hypocrites, Petraeus wasn't the first (or last) executive to have an affair. He also wasn't the first O-10 (four-star flag officer) to run the CIA. He was the first to run things based on real world experience gained in Afghanistan.
There is something about veterans that worries non-veterans. Veterans bring a different ethos and mindset to the job, something I suspect is at work in the case of former LAPD officer Dorner.
Peteraeus biggest mistakes, besides having an affair, was trusting his bodyguards would be as loyal as his military detail. The powers that be did not like the high profile general (something you can see in the press reports). He needed to be removed and the affair provided the perfect excuse.