Collective Marriage (1971)

A married couple is having sexual difficulties. The husband acquiesces in his wife's having a lover who visits her every Friday. The lover participates in a collective living arrangement, where sex as well as household chores are shared. Thinking that they will benefit from a similar scheme, the couple starts their own collective. However, the wife dislikes it when her husband begins to spend time with a younger woman in the collective, and the collective frowns on her having an outside relationship (her Friday lover).