WASHINGTON (RNN) - Gen. David Petraeus, director of the CIA, has resigned from his post due to an extramarital affair.
Petraeus submitted his resignation in a letter to President Barack Obama on Friday.
The letter noted that Petraeus had exercised "extremely poor judgment" in conducting the affair. Petraeus and his wife, Holly Knowlton Petraeus, have been married for almost four decades.
"After being married for over 37 years, I showed extremely poor judgment by engaging in an extramarital affair," the letter obtained by NBC News stated. "Such behavior is unacceptable, both as a husband and as the leader of an organization such as ours. This afternoon, the President graciously accepted my resignation."
In his letter, Petraeus stated it had been "the greatest of privileges" to serve with the agency. He called it "a work force that is truly exceptional in every regard."
Obama will have to nominate a replacement for Petraeus, who has served as head of the CIA since September 2011. He was previously head of allied forces in Afghanistan.
Mike Morrell, deputy CIA director, is the most likely candidate to be elevated to the vacant position on an acting basis, according to NBC News.
Petraeus had reached the rank of four-star general in the U.S. Army before assuming the role of CIA director last year.
Holly Petraeus was also active in affairs dealing with the military. She became the director of the Better Business Bureau Military Line in 2005, working in consumer education and advocacy for service members and also working with the Treasury Department.
She was appointed to direct the Office of Servicemember Affairs in the Consumer Financial Protections Bureau in 2011.