I was going to stay out of this already, but I just had to ask.. WHAT?!?!
So she is going to see him? That changes everything, besides, why in the hell would he be looking at your myspace page anyway? Kick his ass at recess and take his lunch money while you're at it.
Last thing, he's gotten word about you and the not believeing it part, why should he, if she keeps going to him?
I did this shit when I was a kid, I had a girl who would come over, just open my damn door and start humping me, she had a boyfriend, ring all that stuff, and just came to have sex, once a month or so, then she would leave, I didn't care either way.
Shit I was 20 and single, why would I care? I never gave her shit though, I think 1/2 a cigarette, that's about it.