Six and a Half by Eleven (1927)

A renowned doctor and his brother live and work together until the brother falls in love with Marie, a singer, and gives up medicine to be with her. After a time however, she misses her old life and goes back on the stage - an act which leads her lover to commit suicide. Later the doctor and Marie also meet, and she becomes his mistress. He finds out about his brother's suicide and goes through his artifacts looking for a clue as to what might have been the cause. He finds a photograph of Marie and realizes the truth, which decimates their relationship.