
They both have mistakes. I don't condone SA, but Sangnam is a jerk. Does he actually wants to isolate Han Daol? I get the getting mad at being drunk, but the guy can't even hangout and laugh and smile with others otherwise he'll get jealous. While Han Daol felt the same too, his jealousy was towards Sangnam's exes. Okay, sure, that maybe normal in relationship--to get jealous when other people get close to your partner. But mentioning your past lovers while having sex? Yeah, that is definitely a hundred times worse than laughing with classmates. He is selfish. He knows what Daol felt for him. He might have been very clear about what he wanted from the very first, but that doesn't change the fact that he is an asshole.
Ah I feel so emotional rn. I wish them happiness forever.