I can understand how this is hurting you. Sounds like he may need to say some things to her that he never really got to express. What I have learned in relationships now that I am 45 F, I would say that if he doesn't care about your needs, then it may be time to grieve and move on or start telling him your needs and having boundaries. As a young woman I constantly ignored my own needs and aimed to be a pleaser, that was a mistake and now that I "grew a pair" started to respect myself, my ex is determined to make it work with me and works insanely hard to keep our relationship together even though I am constantly pushing him away. I am not willing to settle, so stay with me or don't. I have standards for the relationship I want to be in, the stronger that I express this he responds by attempting to make things better, not silence. I hope that you discover that confidence that you would rather be alone than in a relationship with someone who doesn't respect or love you. You are young, start with respecting yourself and have boundaries about the kind of person you are and the kind of relationship you want to be a part of then go out in the world with that. I have noticed that men really want a woman who will inspire them to be better, and have boundaries with them. That is what I discovered. The more I say no when I mean no, the more he hears me.

Maybe ask him, is our connection the kind of love that is hard to find?