For a three-act plot analysis, put on your screenwriter’s hat. Moviemakers know the formula well: at the end of Act One, the main character is drawn in completely to a conflict. During Act Two, she is farthest away from her goals. At the end of Act Three, the story is resolved.
Act I
During summer vacation on Grand Isle, Edna is an obedient wife, but spending time with Robert Lebrun and Adele Ratignolle is bringing out her less-than-obedient Inner Edna.
Act II
Back in New Orleans, Edna asserts her independence by painting, moving into her own house, and starting an affair.
Act III
Robert comes home and winds up breaking things off with Edna. She returns to Grand Isle and drowns at sea.