Responses
You should know the concept of a non-zero sum. It's not about who wins or loses. In this case, everyone gains something. Actually, Haewon got what he wanted from the beginning, but at what cost? Haeyoung got what he wanted, but he's suffered enough compared to the other two bastards. And no, Taegyom and Hyunwoo don't lose, they get what they wanted to have sex with Haewon without having consequences for their bad actions.
poor MC, his story made me cry and there was no revenge at all, especially for Taegyom, he was the one who started all this
The only peoples who lost were haewon, go taegeom and hyunwoo. Seo haeyoung got what he wanted in the end and he was the most undeserving, The 3 bastard get happy ending with beautiful sex life and haewon became se3 doll