That part!
I mean part of it is that clearly jaekyung has his own issues to deal with before he’s ready to love dan the way he deserves, and Dan needed him. To be open hearted to have his expectations set correctly, which I’m not sure he does. They both have grown a bit, but jaekyung has a complex past to finish digesting
He needs therapy. Like fucking immediately, he needs professional help ┗( T﹏T )┛ (but yeah I also think that is more natural approach than a full "oh you listen to my sad back story and now I'm healed" bullshit)
I get everyone is upset at Jaekyung blowing up kim dan again but personally I like a path to rehabilitation that includes a realistic bumpy road, i personally get pissed off more at stories where a character reflecting has them suddenly and unnaturally start doing the right thing at every turn when they barely understood how to treat others with empathy before being implored to change. So while it might be frustrating in the moment, I actually think that this is better for story in the long and that its a little healthier for the story to have this slight dip in mood lol. Plus jaekyung did show a small, subtle in his immediate regret after saying something awful and lashing out, and choosing to leave the room instead of doubling down. It reminds me of being under the same roof as someone in recovery, healing is slow and rocky and it involves people losing their grip. I like that this is incorporated