been there, was dating a girl for a while, while having a "best friend" on the side who at the time was dating other guys. I eventually decided i liked the company of my "best friend" better than that of my g/f at the time. Broke up w/the g/f, gradually things progressed w/the "bestfriend". Then she got in a serious relationship with another guy, game over.

we don't talk much now, But it was sure a great helluva time while it lasted (almost a year)

you're 20, live it up.