Sticky situation with me, my best friend, and his girlfriend...HELP PLEASE!?

So 3 yrs ago I met this guy in college. We grew to become best friends. We had a strange friendship...it always had some awkward tension. I always felt he liked me, and I liked him very much. Mutual friends teased both of us, always telling him his gf is here (when I walk in) and asking me why my face lights up when he texts and other such things. He even almost kissed me once at a concert we went to together. Anyway, he graduated a semester before me, and moved back to his hometown. A month prior to graduating, he started dating a long time friend of his back home. She's rather cheap, but whatever. We're still extremely close friends and talk almost everyday. Well, he tends to really push the flirting, and I generally stop him. He texts quite a bit and does things like text me pics of sunsets and what not at 5am. Well, the thing that's buggin me is, whenever I write on his myspace or facebook (COMPLETELY platonic messages generally about something regarding school or so), he never replies me. This of course makes everyone think i'm always the one talking to him, when in reality its usually him! Maybe its his gf that is jealous, but if we're friends, its just plain rude. He did it again the other day, and I stopped texting him, and he has been texting and asking what is wrong. What do I do?? I was thinking just be normal, and then the next time he mentions myspace or so, I'll ask him why he never replies me then. Ideas??