The affair between General David Petraeus and his biographer Paula Broadwell ended four months ago, a former spokesman for the general said.
Retired Army Colonel Steve Boylan says Petraeus' affair with Broadwell started after Petraeus left the Army.
Boylan also says Petraeus' wife Holly is "furious" over what happened.
Petraeus resigned as the head of the CIA Friday after the FBI discovered the affair.
The resignation comes just days ahead of when Petraeus was scheduled to testify before the Senate Intelligence Committee over the attack in Benghazi, Libya, leading some in Congress to question the timing. A senior U.S. official told CNN there was no connection between Petraeus' resignation and the hearing.
Other lawmakers have questioned why members of the House and Senate intelligence committees weren't informed sooner; many on the committees said they were blindsided by his resignation. Despite a four-month investigation by the FBI, the committees weren't informed until Friday.
The FBI began investigating the relationship between Petraeus and Broadwell after she allegedly sent threatening e-mails to another woman, who she thought was too close to the general. The relationship between that woman and Petraeus is unclear.
Rep. Peter King, the top Republican on the House Homeland Security Committee, said Sunday that President Obama should have been informed much sooner than he was due to the potential compromise of security.