<p>Sen. John Ensign (R-Nev.) has acknowledged an extramarital affair with a campaign staffer in a statement released by his office. "I deeply regret and am very sorry for my actions," said Ensign. He is expected to announce the affair at a press conference at 6:30 pm tonight. The affair, which was with a woman who worked for both Ensign's re-election campaign and his Battle Born leadership political action committee, began in December 2007 and ended in August 2008. Ensign's wife, Darlene, said that the couple's "marriage has become stronger" and added: "I love my husband."</p>