Prone to Temptation (1986)

After an exasperating fight with her mother, Debbie (Anna Marie Gutierrez) decides to leave home and elopes with Boy (Gino Antonio), the cousin of her boyfriend, Nestor (Julio Diaz). They get married and stay in the house where Boy and Nestor live, distressing Nestor even more. Debbie’s friend, Letty (Jaclyn Jose), has been in love with Nestor for a long time and she seizes the opportunity to get closer to him. After a night of sex, they tie the knot and live in a room next to Boy and Debbie’s.