The Walker(2007)

Carter Page III, a middle-aged gay man in Washington, D. C., is a "walker", a single man who escorts other men's wives to social events so the husbands do not have to. One of the women he escorts, Lynn Lockner, is the wife of a United States senator and is carrying on an affair with a lobbyist. When she finds the lobbyist murdered, she embroils Carter in an investigation that leads to the highest levels of the federal government.