My Uncle (2017)

Byeong-yoon, who lives alone, wants to relieve his loneliness. One day, a married couple living downstairs, Ji-yeon and Go-woong, invited him to dinner. When Byeong-yoon sees the married woman, his heart continues to pound at the thought of her. Go-woong noticed it and made him an offer he couldn’t refuse: a one-night stand with his wife! Though ridiculous, Byeong-yoon still accepts this fascinating offer.