No I agree. I didn't hate him at all and I honestly love how their love was written as tragic and painful but not in a way that they couldn't come back from if that's what they wanted. (Honestly I wouldn't have hated it if this story was their love story)
They were literally teens when they started dating and even though they loved each other they and couldn't keep a love built on curiosity, insecurities, and the bullshit yool's dad put on them both. They had to grow up and I think it was beautiful they chose themselves and to support each other from a distant rather than to drag each other down to a place that would've completely erased the history they had. It showed that flaws aside both characters were mature and caring in ways you don't often see in media period
I rarely like it when characters casually keep around their ex's but from what was shown and the fact they were in similar industries it made complete sense to me. And honestly I want a story about In suh now

I didn't disliked him that much. Even though he was one of the source of mc's worries, the author encapsulates and writes his role so good. He is a well written side character.
Maybe I've read too much bl romance where even if their love was imperfect, they make it work, I'll be lying if I wasn't rooting for mc and in suh lol. (don't throw tomatoes)
Their love story is sad, it gave me a reality check that even if you sacrificed so much for that love, it doesn't totally mean it's enough for a happily ever after.