Strangers on a Train (1951) – Alfred Hitchcock
A slutty wife doesn’t want to divorce her cuckolded husband anymore because he has gotten successful in his career.
Cosplay Cafe (2004)
A young bartender bangs three married waitresses and one widow in the cafe he works in.
Marriage Is a Crazy Thing (2002)
A lady who is already engaged to someone bangs another guy before she gets married, and continues banging him after she gets married. Good love story.