Slippers (1975)

Gregory finds a pair of slippers that he assume belong to a former lover of his fiancée Ginny. She is planning to visit the owner, Philip, who is also her former employer to break off their relationship once and for all. However, when Gregory finds the address she tells him it belongs to her parents. So Gregory decides to visit Ginny's 'parents' unannounced to tell them he intents to marry her.