5x21 - The Nanny

Maxwell's brother, Nigel, is back to throw him a bachelor party, and Fran is terrified because Maxwell doesn't know that she almost married Nigel a year and a half ago. She tries to keep it a secret, but after Nigel gets drunk at the party, he tells Maxwell, just as Fran comes out of the cake in a surprise for him (after Sylvia confessed that Morty cancelled his wedding and ran off with the cake girl - Sylvia!). Fran and Maxwell have a fight over it, and they end up calling the wedding off, until C.C. (under the influence of Prozac) tells Fran that Maxwell didn't spend 5 years ""doing the one man show"". So Fran gets Marla Maples, who had a quick fling with Maxwell a year and a half ago, and confronts Maxwell. They finally realize they love each other and call the wedding back on.