Usefulness of a Childhood Friend summary: I really wanted to get drunk that night. Because I had seen my boyfriend who promised to marry me cheating on me… “Do you like sex that much? Is your self-control so nonexistent that you’d go find another woman and cheat on me?” I’m also going to do it with another man! I screamed, contradictorily… When I opened my eyes, I was met with an unfamiliar ceiling. Then my childhood friend and nemesis… ‘Lee Dohyun’, in his underwear… Why are you coming out of there…?