Not sure if my non-girlfriend counts as "ex", but after reading around and thinking a little I think I finally figured out what I've done wrong. Would tell her this, but wouldn't do me any good I think.
I think I finally get it. Nobody wants to date a guy who can't take the initiative, who always apologizes for everything he does, when he does it, who takes decisions in function of others, and not himself, who does not have a true self-identity.
Perhaps if I had acted more like a man and less like a pushover you would have seen something else in me.. but I can't pretend to be what I'm not. For you I allowed myself to be humiliated, hurt, and eventually heartbroken, and it's not your fault, it's mine, for just being so weak.
Damn, I wish you had never told me you had feelings for me - I became a different person that day: from proud loner to desperate and lonely.