Last week, retired General David Petraeus resigned as head of the CIA, citing infidelity. What's the story behind the married military man's betrayal? In about November 2011, Petraeus – the former top U.S. commander in Afghanistan – began an affair with a married writer, Paula Broadwell. (That was a couple of months after he retired from the military and became head of the CIA.) The pair first met back in 2006 and would spend a lot of time together traveling the world while Broadwell worked on Petraeus's biography, All In: The Education of General David Petraeus.