Con las bragas en la mano (1982)

Marta and Sergio are a couple whose sexual relationships are not going well. To fix this, Sergio asks a friend to arrange an orgy in order to take his wife and observe if she loses her inhibitions. The plan is carried out, and all goes well until one of the guests want to force Marta to lie down with him. To be despised by her and see her husband supports her, he decides to take revenge.