U.S. Senator John Ensign resigned from a party leadership post on Wednesday a day after admitting an extramarital affair with then campaign treasurer, Cynthia Hampton.

Ensign stepped down as chairman of the Senate Republican Policy Committee after holding the fourth-ranking post in that chamber.

He's accepted responsibility for his actions and apologized to his family and constituents. He offered, and I accepted, his resignation as chairman of the Policy Committee, said Senate Republican Leader Mitch McConnell in a statement.

Ensign, 51, described the affair as 'absolutely the worst thing that I have ever done in my life’ as he spoke on Tuesday at a news conference from his office in Nevada publically confessing to the affair expressing deep regret for his action and for hurting his wife.

The affair reportedly took place between December 2007 and August 2008.