Bill and Peter’s Bogus Journey is episode 13 of family guy season 05. It was originally aired on March 11, 2007.
After Peter helps Bill Clinton out with a flat tire, they become fast friends. They begin spending a lot of time together and Lois starts to think Bill is a bad influence. But when she confronts Bill, they end up having sex. Peter is devastated and tries to get back at Lois but finds he loves her too much to go through with having an affair. Meanwhile, Lois and Stewie try to potty-train Brian.