On Nov. 9, just three days after President Barack Obama won re-election and was beginning to tackle several soon-to-be-vacant high level positions on his national security team, Petraeus created a vacancy no one saw coming following revelations an FBI investigation into an online harassment case had turned up an extramarital affair between Petraeus and his biographer, Paula Broadwell.
In a letter to CIA colleagues Nov. 9, Petraeus said he "showed extremely poor judgment by engaging in an extramarital affair. Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours."
With that, the general who'd overseen both the wars in Iraq and Afghanistan, run Central Command and climbed the highest peaks of power in the American military and intelligence establishment was out of the game.
The ensuing days in the Petraeus scandal would take several more bizarre turns, engulfing another top general, exposing a bitter divorce and revealing a rivalry between a pair of socialites whose lavish parties served as a breeding ground for the whole sordid affair.
It began when Jill Kelley, a Tampa socialite known with her husband for throwing over-the-top parties for generals and other high level personnel stationed at U.S. Central Command, told FBI agent friend Frederick Humphries of a series of threatening emails she'd received. Humphries had once sought Kelley's affection, even going so far as to send her a shirtless picture of himself -- a fact that would be uncovered in the ensuing investigation.
The emails made clear Kelley should stop cozying up to Petraeus and other Centcom brass. She and her husband had a quasi-official relationship with the NATO installation in Tampa. Her official title was State Department liaison to U.S. Central Command.
Petraeus and his wife Holly had become friends with the Kelley family, even going so far as penning a letter to a judge in support of Kelley's sister, who was locked in a bitter custody dispute with her ex-husband.
FBI agents in Tampa continued their investigation and eventually traced the emails back to Broadwell. A further investigation found a shared email account she shared with Petraeus, the contents of which revealed the affair.
But the investigation had even greater fallout than just Petraeus. FBI investigators found as many as 30,000 pages of flirtatious emails between Kelley and Petraeus' successor in Afghanistan, Marine Corps Gen. John R. Allen, who had been poised to be named NATO supreme allied commander in Europe.
That appointment is now on hold pending a Pentagon investigation into Allen's conduct. Adultery can be considered a crime in military court. The New York Times said officials have narrowed their focus to 60 or 70 emails between Allen and Kelley sent in a two-year period, beginning when Allen was stationed at Centcom in 2010.
The result of that inquiry is expected in early 2013, the Pentagon said.
As for Broadwell, FBI agents searched the West Point graduate's Maryland home for any classified documents she may have obtained from Petraeus but found none that exceeded her security clearance.
At the FBI -- an organization sensitive to its history under former director J. Edgar Hoover when it was seen as snooping into people's lives -- Attorney General Eric Holder said investigators acted within their purview and properly notified officials of what they found. The agency faced some criticism for failing to notify the White House when they found out about Petraeus' affair with Broadwell.
Holder said the investigation had been undertaken in an "impartial way."
"We follow the facts," he said.