I'm just guessing here... I assume he has a partner and wasn't entirely happy with his relationship and relied on you as a back up for his doubts and frustrations about that. He also probably wanted to boost his ego by knowing that he could attract you, but didn't have the stones to actually make a commitment. He sounds like an emotionally immature individual - and maybe you were his surrogate mother for a time and got fooled into thinking that there could be something else, but don't be fooled again. Move on, move on.
Honestly, it sounds like you make him uncomfortable, even if in your opinion you aren't being creepy or stalkerish.
For your own sake, it might be best to let go of him and move on.
You didn't screw up or creep him out. Do you trully believe you deserve love? If you trully do it will happen . I'm sorry your hurting but this guy is still a great friend for being honest and not leading you on. And because of that he will be back. Because he did not burn that bridge of trust he will have another break with whoever he is with and want to have some fun with u but by then you probably wouldn't want him as much hopeful. The pain is strong but you know it will get better.
Who knows how a man's mind works? I don't.
he knows there will be nothing and he doesn't want to give you hope....he has ended it so that you will stop hurting, or he is uncomforable.
It is time to let him go and move on with your life.
to put simply, to avoid you. your love initially wasn't a honest love where you are wiling to give without nothing to be returned (very normal) and he felt you needed too much from him. Even though you say that you want to be there for him you need to leave it as it is. You have to own your feelings that are very one sided and leave him be. If in luck he values you as a friend he will be back, if not it wasn't a friendship of the long term kind. Find the love you deserve with someone who will give back to you openly and honestly don't wait so long to admit and share your feelings.
Coz you are cancer.
Cuz you are creeping him out. He never saw you in a love kind of way. You screwed up, you should've never waited that long. Should've told him the second you knew for sure. This is just my opinion (a guy)