Should i let this wonderfull guy go or should i fight for his love?

ok i have a problem... i like this boy he is nice ,sweet ,and super i, ur typical Crush the thing is he likes me to, and every time we is together we are unstoppable .. the thing is he has a Little feeling for his ex gf. every time i see him she is all ways tring to get with him weather he is with me or if he is just walken by him self. he would ask me out but she is holden him back... u should hear the sweet stuff he says bout me , he says i am going to change him and we is going to get married he is 4REAL crazy over me it is the kinda stuff u just want to go awwww!! but wat i am haven trouble is that he cant chose a girl he likes,his best friend tell me every thing he says and one day he told me he said he pick me over ANYONE!!!! but i do not under stand y doesn't just pick me.. and 4 get his ex, the only reason he has a little feeling for her is cuz she got an ***.. and the only thing she is good for is opening her legs that's it! idk wat to do, should i give up on him and just let her have him or should i fight for his love [ not physically] ????%3