The Brute (1977)

Glamour model Diane Shepherd gets routinely beaten by her husband Tim, who accuses her of infidelity. When she can't take it anymore, she finds shelter with photographer Mark and his girlfriend Carrie. They introduce Diana to Millie, who is in a similar situation. Meanwhile, Tim informs Diane that if she doesn't come back to him, he will see that he gains custody of their son Timmy.