My Sister is Young Wife (2013)

Synopsis

Brother-in-law, can I sleep with you?" Look, brother-in-law, we are finally united. I had been wanting to devote my life to protect my only sister-in-law, Hikaru (Sakura Aida), but she had gotten married and had lost the will to live. I had devoted my life to protecting her, but now that she was married, I had lost the will to live. One day, Hikaru and I came home after a quarrel. I was so happy to see him. For just one night, Hikaru and I became lovers...