Won's personality does get better. But keep in mind his personality is due to his entire life being abused and repressed. He finds love and happiness for himself but then his abuser (father) takes that happiness away in such a cruel way. And then almost promptly after his father dies in front of him.
So I think it'd be unrealistic if Won was capable of being happy, stable, healthy from this point.
There is no magic pill. There is so much story left in the novel which allows for a realistic timeline of Won getting better.
I recommend sticking with the story. Its really good!
Thank you for your honest reply, unlike Morphinoce's (I can tell you care a little too much about this story, but thats okay, I too have story I'm like that with).
So thats good to know! Im aware of Won's history and as someone who personally went through abuse from my own parents, I know where Won is coming from. But what im upset about is the fact that he is refusing to work on himself for the things he loves, given the timeline of their love story. So I am happy to know that he will change. I hate stories where the mc refuse to change but the ml continues to love them regardless and it ends there.

Can novel readers tell us: is Won's personality going to get better? Please spoil that for me! Because at this point, im about to drop this. Cause what do you mean you selfishly asked him to wait and then have a rebound with someone else? What do you mean you selfishly cyber stalk him and then have the audacity to moped your life away? What do you mean you didnt contact him because you both live in different worlds? Nah. Excuses to keep the plot going. Its not like one of you is a son to a rich family and the other someone so poor they are willing to pretend to be someone else for the summer for some money. Its not the same. So please spoil it to me and tell me Won is going to be a better person and make up for all his shitty-ness because, like someone else said, Seo deserves better at this point.