Natural Enemies (1979) on Netflix

Plot summary

Paul Steward is forty-eight and edits a magazine. He and his wife Miriam have slept apart for eight months, and Miriam has attempted suicide and has had shock treatments. Miriam drives him to the train station, and Paul says that no tenderness remains between them and that only their children keep them married. He has passed a sleepless night at the isolated Connecticut farmhouse and has decided that before the day is over he will take a rifle and kill Miriam, their three children and himself. At the office a former astronaut seeking to write an article describes the loneliness of the moon, and Paul finds a connection to his own torment in it. Paul also speaks with a friend, a Holocaust survivor, about men who kill their families.