Sssnoopyyy:
TBH, XY has her issues and should not even be in a relationship with anyone because she has so many things to work through herself. Many ppl talk about the guys but she has her flaws as well.
All 4 main characters experienced traumatic experiences; some are just more "healed" than others. XY needs extensive therapy and so does Jing - these two are the sickest of the quartet. Jing in particular, needs a complete overhaul.
Out of the three relationships, XiaoLiu is probably the healthiest if nothing more than because XL doesn't define himself by his relationship with XY in the same way the other two do (CX less so). And he doesn't need her either. Under different circumstances, he would have been the best person to help her heal and grow. In the current circumstances though, their relationship is rather unhealthy for XL. In the real world, I would want him to be done with XY's dilly-dallying a long time ago. The amount of times in the novel that I wish he would sever the Lovers Bugs connection and be done with her is too numerous to count :-).
But yeah. It's fiction so we go along with certain that we wouldn't in real life. Except for Jing! He's unacceptable be it fiction or real life :-).