70’s or 80’s Romance movie.

80's or 70's romance movie. The young couple would race each other back to their apartment as a fun ritual in their relationship. The girl would usually arrive first and win. • I remember one specific scene where she caught him cheating with another woman on l stage, after showing up to find him. I think he was aspiring to be an actor. • The plot was the man was unfaithful in the relationship a lot, and the girl stayed with him. But by the end he didn’t cheat anymore. He •The man had black hair and kind of a slimmer John Travolta build. He wore super short grey workout shorts once in the movie. And the woman had blonde hair, but cut into a layered almost shoulder length bob.