Thomas (1975)

In Troyes, Thomas, the son of a bourgeois family, is in the final stages of his adolescence. He's almost an adult when he discovers that his mother has a lover. At the same time, he realizes that his father is turning a blind eye, and that the estranged couple are only together for show. Thomas rebels, but has to hide his dismay and satisfy his great need for tenderness at the same time.

Unfortunately the movie Thomas is not yet available on HBO Max.