Swing High, Swing Low (1937)

Story in a nutshell: American slacker just out of the service (Fred MacMurray) meets a pretty girl (Carole Lombard) on a short layover in Panama. She shapes him into something worthwhile by, you know, believing in him and stuff. He takes his new-found confidence and trumpet-playing gifts and leaves her behind. She keeps the faith for a while but he eventually loses her. So he falls on hard times because she was the only good thing in his life. Because he's now pathetic again, she goes back to him. Somehow, with her in his arms, he gets his trumpeting mojo back.

I can only assume the cycle repeats in perpetuity. Sorry if I spoiled anything.

D+