Thanks for the responses. i guess maybe i'm in the wrong section of the forum then.
I did some research on bpd. It does fit things pretty well with him.
I figure that it's kind of odd behavior to act like you love someone for one night, thought it was the beginning of starting anew again between us only to be pushed away once again, as if everything he said and did was fake.

It's hard to see him in pain, and hard to see people around him making fun of him. I don't know if he has a substance abuse problem, but i do know he drinks heavily. We've never openly discussed if he has an issue or depression, because he doesn't often express his feelings or wouldn't risk hurting his pride or appearing weak.
Which makes me so sad, because i'd be here for him through everything, but I guess all I can do is take a step back and hope he can recover.
It's just so hard loving someone so much and envisioning a future together only to have them keep running away from you and to see him hurting.