You're right, he did. I'm referring to the leaks (which admittedly he may not have had anything to do with), the public statement from CIA, and Broadwell's public statements.
It looks to me like someone decided he had to go, whether him or them. He revealed the affair to keep them from revealing it first.
I rather thought the opposite at the time; how did they get Petraeus to go along with such an obviously phony line as the whole "you tube" story? I don't remember, was he under oath for heaven's sake? I'm imagining his willingness to go along was starting to fray. I'm not sure I understand yet exactly how this all hangs together but that it is related I don't doubt for a moment.
I don't believe in a disinterested FBI investigation that just happened to topple the CIA Director. A government that is running guns to Mexican and Honduran mafias, and Al Qaeda all over the middle east, isn't going to be too concerned that their spymaster is sleeping with his biographer. Mainly when they knew it all along.
I hope he comes out and testifies the whole truth, but I have no faith hat he will.