The Love Boat (1977)

S2E15 Second Time Around/The 'Now' Marriage/My Sister, Irene

Doc's former wife enlists the help of an actor who immerses himself in his character a little too deeply, posing as her fiancé. Meanwhile, the wife of a cheating marriage counselor turns to Captain Stubing for comfort. Additionally, a woman decides to masquerade as her own sister to reconnect with a long-lost love during a reunion.