Love Now (2007) aka Changing Partners
Two affluent couples unknowingly change partners.
Actors: Uhm Jung-hwa
Five Senses of Eros (2009)
Three young couples test their love by permuting partners for a day.
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.