I've Heard the Mermaids Singing(1987)

Scatterbrained Polly gets a job as a secretary in Gabrielle's art gallery. Polly aspires to be a professional photographer, and idolizes Gabrielle for her artistic ability. When Gabrielle rekindles an old romantic relationship with the younger painter Mary, Polly becomes jealous, and discovers Gabrielle isn’t exactly who she claims to be.