I like this boy but he has a girlfriend.?

ok, so im in 7th grade and i'v liked this boy for along time. my other friend thinks he is a man because he does date ALOT of girls. i cant help that i like him so much. but my best friend is datin him right now, and its really annoying cause they break up and get back together soooo many times. i do really believe he likes me back, but hes happy with his gf now. i just dont kno what to doo.he says he wont go back to his ex but he always does...which is also annoying. i wanna date him reeeeeally bad. but idont kno what to do. /: