My Friend's Wife(2018)

Original title: 내친구 아내

Min-ah and Jin-sung have been married 2 years, but Jin-sung can't get an erection no matter what Min-ah does. Min-ah's sexual appetite ibuilds until one day, Jin-sung gets a call from his friend Oh-hyun. His business failed and he was kicked out of the house so he needed a place to stay for a month. Oh-hyun came with his wife a few days later, but Jin-sung gets an erection as soon as he sees her. Min-ah suggests a shocking deal.