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
Henchard sells his wife and daughter to a sailor and ruins the reputation of a young woman in Jersey.
Act II
More marriage problems. Henchard is reunited with his wife and daughter. When the wife dies, he's free to marry the young woman from Jersey. She doesn't want to marry him anymore and marries his rival instead.
Act III
Henchard's past relationship with the young woman is made public and she dies of shame. Henchard's rival remarries Henchard's stepdaughter. Henchard leaves Casterbridge and dies alone.