A look at 15 unexpected resignations throughout history

In November 2012, CIA Director and four-star general David Petraeus resigned from his CIA position after admitting to an extramarital affair.

An Associated Press report said the FBI discovered the relationship by monitoring Petraeus' emails after being alerted that Petraeus biographer Paula Broadwell might have had access to the account.

"After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair," Petraeus said in a letter released to the CIA workforce. "Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours."