My Friend’s Older Sister (2016)

Jua and Minsu, who are in an affair. They are also friends with their respective spouses. The couples—Jua and Haeil, and Jinhee and Minsu—go to a pension to hang out, but they have no interest in their own partners. People who somehow send their partners away to enjoy their illicit relationships. People who make all sorts of excuses to get rid of each other, getting them drunk and making them pass out. People who secretly indulge in sex with each other.