Dosukebe kaseifu: Kahanshin nugui (1994)

A salaryman who divorced his first wife and remarried. However, because he lives with his college-aged son from his previous marriage and his elderly father, he rarely has sex with his wife. Frustrated, the man stops by a telephone dating service on his way home from work and manages to arrange a meeting with a mature woman. This woman is incredibly sexy and extremely lewd, and the man becomes completely infatuated with having sex with her. Meanwhile, at home, his wife asks if he could hire a housekeeper because taking care of her father is difficult. The man comes up with a brilliant idea. He'll hire that sexy mature woman as a housekeeper, and then he'll have a harem with his wife and mistress living with him...