Rabbit in the Pit (1969)

Leslie, a talented ballerina, has been having an almost incestuous relationship with her mother's lover for quite some time. Torn between sexual desire and disgust, Leslie's relationship with the tyrannical and voluptuous Maurice soon weighs on the (actually only pro forma) relationship between Maurice and Francine. One day, Leslie's salvation comes in the form of the restless, roughly the same-age performance artist Brian. When both young people fall in love with each other, Maurice reacts jealously and Leslie has to decide with whom she wants to stay.