Room at the Top (1959)

The English factory town is dreary but Joe Lampton has landed a job with a future. To have something to do at night, he joins a theatrical group. His boss's daughter Susan is playing ingenue roles on stage and in real life. She is attracted to Joe, who thinks about how much faster he will get ahead if he is the boss's son-in-law. This plan is complicated by his strong desire to be with an older woman who also belongs to the theatrical group; she is French and unhappily married. Joe believes he can get away with seeing both women.