All this

not everyone can afford medicine and therapy but I do agree that you should fix your own issues before entering a relationship.

but he has a supportive boyfriend who is willing to help him financially and every way so he can afford medicine and therapy, although maybe it’s unhealthy to rely on your partner like that sometimes it’s alright to accept help like that

true although i thinks it’s because dan doesn’t really see jaekyung as a supportive boyfriend right now but someone who he has a debt to

When you've grown fully accustomed to resolve everything, every single and little thing, on your own since you were little with no help whatsoever it's difficult asking for help. It takes a strong will and a fierce battle against your instincts and anxiety to say "I need help, I'm not okay, I cannot manage this on my own" because it makes you feel vulnerable. Furthermore, I think that Woo-won has been suppressing his feelings and self for a long time in order to be liked, to not be a bother, to feel useful. It's worse when it's the person you really love because you want them to see your best but you're afraid they'll leave at your worst even if they tell you and show you that they'll be still there. You cannot believe that because no one was there before, they always left. Add some abandonment issues (the father left, the mother left for a few days, his girlfriends left, the one thing he loved had to be given up), add physical and emotional abuse for we don't know how long... I'm pretty sure he has disorganised attachment and now that he's not in a pretty place it's biting his ass and messing with their relationship.
Having a rich boyfriend willing to help you does nothing when you battle against yourself and your demons and your inner voices... What he needs is realising that he needs help, professional help, and solving all his traumas with therapy.
You cannot blame him for his actions, you cannot say he's wasting time and being a burden because that's precisely what gives more trauma to the person.
He does have a rich boyfriend willing to help but who is toxic AF too and also needs therapy. Instead of trying to understand and empathise with Woo-woon he blames him and then showers him with love and care and "I'm so sorry" and then when Woo-woon does something he doesn't like again we repeat the pattern.

Someone who practically had to raise themselves with no help doesn’t know what unconditional love is they have trouble asking for help or admitting they need it and having it done can make them uncomfortable or feel the need to run

Then Seo an would have, has he?