One from the Heart (1981)

Hank and Frannie don't seem to be able to live together anymore. After a five-year relationship, lustful and dreamy Frannie leaves down-to-earth Hank on the anniversary of their relationship. Each one of them meets their dream mate, but as bright as they may seem, they are but a stage of lights and colors. Will true love prevail over a seemingly glamorous passion? Welcome to Coppola's Broadway-like romantic musical.