What is up with this guy?

I’ve liked this guy for about 5 months now and he knows it,I took it upon myself to tell him I liked him,he told me all he could offer me is friendship because he had a girl ok,fine,he told me he appreciated me telling him myself, my friend said he was all flattered and smiling from ear to ear..fast forward about 4 months,the wednesday before all heck broke loose,he was really flirting with me big time(I have witnesses),then the next day when I wasn’t there,he goes up to my friend and asks her whats up with me that I seem to be pressuring him,I wasn’t,I have back up on this too,I never touched him on the arm,I kept space between us never got up too close,we just picked on each other all of the time and acted like the friends we agreed to be,anyway,he tells her to tell me to not even talk to him,he doesn’t even wanna be friends,and to leave him alone,yes,I figured his girl found out and had a cow,but why didn’t he come to me? He still asks my friends if I’m working or still around,I ignore him and turn my back to him when he comes into the same room,he clears his throat..sorry so long,but it;s the only way could explain,so whats up with him? Is he just a snake are what?he’s getting on my freaking nerves…=-\