Ever since forever, Sunghoon was in love with you but you never noticed it. He was too embarrassed to talk about it and walk over to you. It lead him to the severe depression and hospitalization, especially when he saw that you were getting married which lead him over the edge

after two years you were in the mall, just shopping. Your husband was cheating on you so you were starting the process of divorce and felt bad and lonely. You saw Sunghoon, your old classmate shopping and reading the ingredients on packaging. You walked over to him to catch up. He was talking awkwardly as always and he said "oh hey..it is really nice to see you again, I know you are married so...how is it going?"