He slept with his ex ON YOUR BIRTHDAY? Plus you're saying he's a selfish person who has no problem using others to his own gain? Run, run, run away.
Pretty much that was the clincher for me.
At best, he did it innocently and will continue to do hurtful things such as this out of ignorance in any continuing relationship; at worst, he did it on purpose, making it doubly sure you should move on and find someone who respects you as a human being.
It sounds to me that you're confusing yourself because you just really liked him and didn't want to cut things off necessarily. We all can feel that way sometimes, but in the end, it sounds like you are only going to be hurt and taken advantage of in this particular relationship.
in other news, he's started dating a girl 14 years his junior. just, awesome. i found out because he put a pause on seeing me when he met her. two weeks later, when we finally talked about the obvious fact that we weren't dating anymore, he said: "in some ways, it's easier to date her than you because she has no expectations and doesn't want a relationship." he also admitted (when i pointed it out) that he started dating me too soon after he and his ex broke up, yet insists that i wasn't a rebound relationship. that he wants me in his life long-term, "in whatever form that may take."
this is way high school but he actually texted that girl from the cabin, making plans to see her the night he got home! we'd agreed to turn off our cell phones so i asked what he was doing and he told me he was texting her...
Yeah. Exactly... Glad it seems to be "over"... although it's clear your heart is still kind of wishing it wasn't.
don't think he's done the analysis required to know what he wants. and the longer i stick around, i somehow think the longer it prolongs his indecision. i have no idea why but maybe it has to do with missing me, as INTP said.
I was going to respond to your WAAAAY earlier question in the OP about him saying love was grayscale for him.
I don't know what type he is, but for me as a P, I had a lot of trouble deciding whether I love(d) someone or not. i could even be in LTRs, and even married, and still wonder whether I should be with the person and actually loved them. The problem is that I needed to analyze it... and i had no real litmus test for what "love" actually should feel like, so I couldn't tell if my analysis would match up with what "love" was supposed to be.
I could feel very intently about someone. I could want to be with them. I could commit my life to them. And still not be sure if what I was feeling was love. Frustrating as hell, not just for me... but also for those who knew they loved me... and it would leave me feeling so guilty and horrible that I would want to bail simply so that I would not hurt anyone else. I don't want to use people, and if I didn't really "love" them, then I didn't want to have them commit to me and maybe get hurt some day.
i think at some point I reached a stage where i just realized that love had a large commitment aspect, rather than just being a "state" of self. I could bridge the gap over my doubts by simply choosing to commit, and this would compensate for my lack of ability to measure my feelings quantitatively. And whoever I chose to love would be a person I loved. That was it. Love was a choice, once basic criteria were met.
EDIT: In any case, I need to say (in response to your very last post here) that, if he has not reached that stage (which it sounds like he hasn't), then your remaining around IS going to confuse him. He will have good feelings toward you, he will want to be physically intimate, he will want to engage you if you are there... all while not being willing or able to commit... so it will just make it harder for him to move on.
Honestly, for his sake and yours, I would just call a temporary moratorium in seeing each other even as friends. He needs to move on... and so do you.