Jukuzuma to aijin: Zetsumyô sukebe shita(2012)

Overview

With her husband Shinsuke's business in a slump, his wife Aiko decides to rent out one of the rooms in their home. While she, a chiropractor, is busy with work, Shinsuke is having an affair with the young Hitomi. Hitomi appears in front of the unsuspecting Aiko, saying she saw a sign saying "Room for rent." Shinsuke and Hitomi pretend to be meeting for the first time, but they end up having sex whenever Aiko isn't looking.