If Petraeus STILL does not testify as a private citizen, then he is the one who stinks. He can in that case join John Roberts as another traitor who stabbed America and made it bleed.
Or:
Possible scenario: something bigger is happening, and there is no mistress. The administration is blackmailing Petraeus in some other "Chicago-style way," and tells him to resign with this phony admission. He then will take the Fifth Amendment, if subpoenaed by Congress.
Possible scenario B: there is a mistress, pro-MAObama forces used it as leverage to keep the lies coming about Benghazi, Petraeus has resigned to expose the lies as a private citizen. He has been the source of the leaks.
Timing is everything!