The FBI's startling disclosure about the extramarital affair of David Petraeus, who has resigned as CIA director, has raised many further questions, particularly over the timing of his resignation.

Petraeus's resignation comes just a week ahead of his appearance before the Senate Intelligence Committee at a hearing on the Benghazi attack in which four Americans, including US ambassador to Libya Chris Stevens, were killed.

The CIA has been blamed for a failure of intelligence to anticipate such an attack and for terming it as a backlash against the anti-Islam YouTube video Innocence of Muslims rather than a terrorist attack. Petraeus was due to face a grilling in Congress, but the task will now pass to acting CIA director Michael Morell.

The White House maintained that it became aware of the Petraeus situation only on election night, and the president was informed on 8 November.

"David Petraeus testifying has nothing to do with whether or not he's still the CIA director, and I don't see how the CIA can say he's not going to testify," House Homeland Security Committee Chairman Peter King (R-N Y) told CNN.

"He was at the centre of this and he has answers that only he has."

The Other Woman

The FBI unearthed Petraeus's extramarital affair with his biographer Paula Broadwell while investigating a cyber harassment complaint the agency received from another woman. The alleged harassment was traced to Broadwell.

The agency uncovered explicit mails between Broadwell and Petraeus, one even referring to sex under a desk. The FBI began monitoring his Gmail account to check whether his email had been breached.

The other woman was reportedly close to Petraeus but the nature of their relationship is yet to be made public.

The extent of the breach of Petraeus's private email account, if any, and the content of his emails are yet to be divulged.

Family Man

Petraeus's affair with Broadwell is "'unthinkable" to many of his aides as he always maintained the image of a gentleman and a family man.

"I spent a lot of time with him, and I never heard him say, 'Wow, she was hot,' " one former aide told the Washington Post.

"I never recalled hearing him say anything crass or even mentioning the good looks of a person."

Friends and acquaintances of Broadwell, a Harvard University research associate and PhD candidate at King's College, London, described her as high achieving, smart and intelligent who is passionate about the causes she promoted.

Broadwell has a military background and graduated from the same West Point Academy as Petraeus. She served in the army for over a decade and achieved the rank of major before joining Harvard.

She is married to radiologist Scott Broadwell and has two sons. She lives in Charlotte, North Carolina.

Petraeus is married to Holly, the daughter of a West Point superintendent who heads the office for service-member affairs in the Consumer Financial Protection Bureau, an agency created by the 2010 financial regulation law.