Reading this was a toughie (had so many times I wanted to drop this while reading). After reading it through the end, I get why the authors went with that direction. Yahwi and Jooin's relationship remained in limbo, while Cain's was clear cut from the very beginning.
Still, I think it would have been best for the 3 of them to go separate ways and start life over with new people that are better for them (e.g. Jooin meeting someone who reciprocates love without getting hurt, Yahwi treating someone good becoz of his past mistakes, and Cain loving someone naturally). Just my 2 cents!
I know people are divided in the comments about this one but I honestly liked how it ended. After reading the last chapter, it felt right TJ and Ian are endgame. Of course my heart hurt for Jo (my poor baby), but I doubt Ian would be as happy as he is now with Jo had they left that night and continued to be together. Jo may find someone else but it's highly likely Ian would not. That's probably why author chose TJ as endgame. I feel so bad for Jo, but I'm sure he'd be able to bounce back and be loved by someone better. It was tragic, but it ended the way it should have.