Stress is Three, Three (Stress-es tres-tres) (1968)

A married couple and a male friend leave together on a weekend vacation. Stress is brought on by the husband's jealousies. He hopes to play out his fantasies with his friend and wife in order to justify revenge. Geraldine Chaplin, Juan Luis Galiardo, and Fernando Cebrian star in this odd tryst that is heavy on insects and the voyeuristic machinations of the husband's mind. ~ Dan Pavlides, Rovi