The government watchdog group Citizens for Responsibility and Ethics in Washington said it will file a complaint to the Senate Ethics Committee this week regarding Sen. John Ensign (R-Nev.).CREW Executive Director Melanie Sloan said Monday that the group will file a complaint midweek requesting the panel to examine the dismissal of former aide Doug Hampton and his wife, Cindy Hampton, whom Ensign recently admitted to having an affair with in 2008.Ensign, who acknowledged the affair Tuesday, was back on Capitol Hill on Monday. The Nevada Republican last week relinquished his post as the GOP Policy Committee chairman but has given no indication that he plans to resign his seat in the Senate. Details about the relationship are continuing to emerge, but Ensign’s office on Friday charged that Doug Hampton sought cash from the Senator in exchange for his silence about the affair. Sources say Ensign decided to go public about the relationship on learning that Doug Hampton was trying to shop the story to the media.