( CNN ) -- Only two people know how the affair started , but the world knows now about its inglorious end . Admitting to the extramarital affair , David Petraeus stepped down as director of the CIA on Friday in a surprise move that shocked the intelligence community just days after President Barack Obama was re-elected . Immediate praise for the man poured in . The president hailed Petraeus ' dedication and patriotism , while leaders from both parties said he would be missed . It appeared an abrupt end to a spectacularly successful career in public service . `` After being married for over 37 years , I 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 , '' Petraeus said in a letter to colleagues , explaining his decision to step down . `` Teddy Roosevelt once observed that life 's greatest gift is the opportunity to work hard at work worth doing . I will always treasure my opportunity to have done that with you and I will always regret the circumstances that brought that work with you to an end , '' he said . According to a U.S. official , the FBI had a tip that Petraeus was involved with his biographer , Paula Broadwell , and investigated the alleged affair to determine whether it posed a security risk . The FBI was not investigating Petraeus for wrongdoing . The concern was that he could potentially be blackmailed or put `` in a vulnerable spot , '' the official said . Broadwell spent a year with Petraeus in Afghanistan interviewing him for the book she co-wrote , `` All In : The Education of General David Petraeus . '' It is not clear whether Broadwell is the woman with whom Petraeus has admitted having an affair . CNN has not been able to reach Broadwell for comment . Other sources close to the CIA director told HLN anchor Kyra Phillips that the woman involved in the affair was not under Petraeus ' command . The woman was not a member of the armed forces and not a CIA employee , they said . Petraeus , 60 , had a distinguished 37-year career in the military before joining the CIA , helping turn the tide against insurgents while commanding forces in Iraq and Afghanistan . Earning praise from both sides of the political aisle , the retired four-star general took the helm of the CIA in September 2011 . Politicians react to the resignation . Director of National Intelligence James Clapper hailed Petraeus , saying his `` decision to step down represents the loss of one of our nation 's most respected public servants . '' Petraeus met with Obama on Thursday to offer his resignation and explain the circumstances behind it , according to a senior administration official . The president accepted Petraeus ' resignation during a phone call Friday , said the official . `` By any measure , he was one of the outstanding general officers of his generation , helping our military adapt to new challenges and leading our men and women in uniform through a remarkable period of service in Iraq and Afghanistan , where he helped our nation put those wars on a path to a responsible end , '' Obama said in a statement . `` As director of the Central Intelligence Agency , he has continued to serve with characteristic intellectual rigor , dedication and patriotism . '' The president expressed confidence that the CIA will continue to move forward , under the direction of Acting Director Michael Morell . Morell , a career agency officer , was sworn in as deputy director of the CIA in May 2010 . He previously served as associate deputy director and director for intelligence . Petraeus assumed command of the NATO International Security Assistance Force and U.S . Forces Afghanistan in July 2010 , after serving for more than 20 months as commander of United States Central Command . He previously commanded multinational forces in Iraq , leading the so-called surge . The general literally wrote the book on counterinsurgency techniques by overseeing development of the Army/Marine Corps Counterinsurgency Manual . Before his nomination as CIA director , Petraeus was considered the nation 's most well-known and popular military leader since Colin Powell . But his reputation was potentially tarnished by the controversy over the terror attack on the U.S. mission in Benghazi , Libya , that killed Ambassador Christopher Stevens and three other Americans in September . Petraeus was expected to testify before the Senate Intelligence Committee next week on the Benghazi attack . Morell will take his place , according to the office of Sen. Dianne Feinstein , who is chairman of that committee . `` I wish President Obama had not accepted this resignation , but I understand and respect the decision . David Petraeus is one of America 's best and brightest , and all Americans should be grateful for his service , '' she said . Rep. Peter King , chairman of the House Committee on Homeland Security , described Petraeus as a `` true American patriot . '' `` This is a real loss for the country ; a real loss for the CIA , '' he told CNN 's Erin Burnett . Petraeus and his wife , Holly , live in Virginia . They have two grown children . CNN 's Carol Cratty , Terry Frieden , Suzanne Kelly and Jill Dougherty contributed to this report .
David Petraeus , a retired four - star general , commanded forces in Iraq and Afghanistan . Source : The FBI received a tip that he was sleeping with his biographer . President Obama praises Petraeus ' dedication and leadership . He and his wife , Susan , live in Virginia , and have two grown children .