Glück im Hinterhaus (1980)

Karl Erp is a middle-aged man with two children and a boring marriage. After starting an exciting affair with his intern, Miss Broder, he leaves his loveless marriage and moves in with his lover. Under pressure from Miss Broder’s mother, Karl once again promises marriage. He finds, however, that the excitement that drew him to her in the first place doesn’t carry over into their daily lives.