Why is he d8ing me ?

Because you two have been friends for so long, maybe he just feels very comfortable with you and does not feel like he has to constantly reassure you of his feelings for you. You need to trust the fact that there is a reason why he is with you and not his other girlfriends. You have been friends for so long and clearly he really cares for you. If you still don't feel confidant with your relationship, be honest and talk to him about it.You are close enough where you should be able to tell him exactly how it is that you feel. Good luck.

Maybe he is one of those guys  that just like to hold many girlfriends near him. Do you think he is having the same relationships with other female friends he has? I think this guy might not be able to say goodbye , he kept you near him all time so you might date him when he feels lonely .It is no shame to ask for something that will make you trust him.

if he acts wierd around another girl  dump him

Hello, 

It sounds to me like he wants to be with you. If he has other opportunities and he still chooses to stick it out with you, I would say there is great promise. The fact that this is your second time around is also important since, after braking up, you both had time to think about what you want. 

I feel the problem is you don't feel the things coming from him are sincere. You have to ask yourself why you don't believe him when he says things like "I love you". I think thats the key. Try and define for yourself the things that bother you. After that I would talk to him about it and see how he reacts. You can't keep these feelings bottled up for very long. Sooner or later they'll affect your relationship (If they haven't already).

I wish you the best of luck.