I need help NOW...he is asking me what is wrong as I type!!!!?

My best guy friend of 3 years...well i've always liked him. Before we were friends even, I liked him. The closer we grew, the more I liked him. People thought we were pretty much dating, we were that close. I thought he practically loved me. We were inseperable! But he graduated before me and moved back to his hometown. A month before he moved, he began dating a girl back in his hometown. After a while of disagreements, we remained verrry close friends. I never told him how I felt, as I felt it was the best way to remain strictly friends. I have done everything I can to keep things platonic, though he often pushes things with the flirting. The thing is, whenever I write on his wall on myspace, his girlfriend goes insane and has to write a million love messages to him. I don't say anything not friend like...in fact its usually just homework questions. We're strictly best friends as per my knowledge. But he'll text me til 4am and what not, and diss me on facebook, making me look like i'm psycho trying to talk to him while he's really the one doing it. I know that's not his motive. But he did it again, and I'm pissed beyond believe. He's been texting to suck up, and he finally gave up sucking up and asked me "what's the matter?? something is wrong i know it." What do I do?? I can't tell him its cause of his gf, cause he'll think I'm being jealous and crazy...not to mention I don't want to scare him off.