Petraeus knows "this was poor judgment on his part. It was a colossal mistake. ... He's acknowledged that," Boylan said.
One result is that Petraeus could possibly face military prosecution for adultery if officials turn up any evidence to counter his apparent claims that the affair began after he left the military.
But Boylan says the affair between Petraeus and his biographer, Paula Broadwell, both of whom are married, began several months after his retirement from the Army in August 2011 and ended four months ago.