The usefulness of a childhood friend

Summary

That night, I really wanted to get drunk. It had been the day I saw my boyfriend —the one I had planned to marry— cheating on me... "Do you like sex that much? So much that you can't hold back and have to find another woman?!" Then I'll sleep with another man too! I shouted at the top of my lungs, but... When I opened my eyes, I found myself staring at an unfamiliar ceiling. And in front of me, in his underwear... Was Lee Dohyun, my childhood friend and eternal headache. Why are you here...?