Hye-shin and Seong-min, a couple who have painful memories of their childhood. They are an affluent couple but want to forget their painful memories and dream of a departure. So they allow each other to date different persons, initially for fun and to challenge each other, but suddenly it becomes emotional when the guy whom the wife dates turns out to have a link from her past.
Cheating Notes
At the beginning of the film, the wife and her husband dance with other people on the dance floor, grinding against them, to get each other excited. This leads to them having sex in the parking lot.
The couple allows each other to date other people (only one person each), initially for fun or maybe to put excitement into their relationship since their sex life is getting stale. I'm not sure if part of their deal is that they can have sex with their respective dates. If I have to guess, it doesn't seem so. They usually bring their dates to the same venue (cinema or restaurant, for example) so that they can observe each other, but of course, they pretend that they don't know each other. Because of this, their sex life improves and they fuck more enthusiastically than before.
The guy whom the wife dates is a geeky photographer with eyeglasses. When he reveals to her that he is someone from her past, specifically, he is a stalker (but of course, he wouldn't admit that) who took a photo of her in high school when she was crying while running in the rain after a fight with her boyfriend (now husband), she becomes emotional and allows him to kiss her (39:06). When she comes home, she is still emotional and fucks her husband passionately.
Now, what's left to decide is if both wife and husband will go all the way and fuck their respective dates. Will the geeky-photographer-slash-stalker get luckier and bang the wife?
With several sex scenes between husband and wife.
Link please