this guy sounds so extremely self focused, and maybe not able to emotionally sustain a real relationship, who knows?
in time, as you move away from it and can get a better perspective, I hope you'll be able to see that what he did is much, much more about him and not you. that might help with the jealousy and loss. you just may be more sad about the guy you IMAGINED he was, rather than who he really was (unfortunately!)
in these types of situations, it's really easy to let yourself get caught up, and to let things escalate. you can move forward making choices you might be happier with from now on, so you can feel good about it in the future.
I feel especially especially especially sorry for that poor kid, who has be in the middle of all this upheaval and have that be his role model.
so sorry you had to go through that!