WASHINGTON — In closed sessions before the House and Senate Intelligence Committees on Friday, David H. Petraeus apologized to lawmakers about his affair with Paula Broadwell, which led to his resignation last week as the director of the Central Intelligence Agency, but lawmakers said later that they did not ask about the matter.

Instead, the focus of both hearings was the attack on the American diplomatic mission in Benghazi, Libya, two months ago that killed Ambassador J. Christopher Stevens and three other Americans.