I honestly think he's still just pretty immature, despite the looks, there's still just college students anyways. He's scared of getting hurt because of a bad breakup, he'll get over it eventually. Life goes on.
Indeed. It's just like Chanwoo had to say that life 'moves on" if things don't ever work out with Jiwon, DG doesn't seem to accept/know this, just like how Jiwon hasn't been able to emotionally recover and progress from his break up. The may be adults in their mid 20's? but as you say, they are still quite naive meaning they don't have this c'est la vie/such is life approach. Whereas Chanwoo and MD are obviously a lot more self aware and secure and honest with themselves, which is a marked contrast, so hopefully there will be some more chapters with them.
Alex is being a jerk. Not all relationships end bad.DJ even lied because he dose not want to separate from you.HE WANTS YOU GOD DAMN IT.