Break up or Give him another chance.?

I am 14 my bf is 13 he kissed me while he had a gf about 8 months back and it happend a few times. well he broke up with her for me and asked me out Dec 11 2010. Well the past few months have been DRAMA!!! his bestfriend is the brother of two girls my age who are sluttly drugys who say they lost their V to a highschool. well he spent the night over there and was really flirst with G one of the twin sisters. well everone says he was cheating on me with them. well he was PISSED about it all and now after all the drama he walked away from the two girls who where his friends. Well now they are no prob in our relationship now it is a slutty girl named Mckenna who likes my bf and flirts with him all the time. she is always talking bout him and he CUPED her in a car the first month me and him started dating well i never told him but it furiated me that he did that. well just with in the past 3 weeks i have let it all out. i told him i hate mckenna and that if he keeps acting like that with her then im gonna dump him, well just last week he was on the bus with her comeing back from a chorus trip. she was sitting with her legs apart facing him he was fasing the bus driver and her leg was touching his leg. well he started messing with her leg in a flirty way and my friends saw him. that day i told him "i love you ****** but i wont do this. if you want me as a gf you cant do that. you have come to the point i cant trust you. im not dumping you,,, yet... but we are taking a break for a while." he was quit the hole time. i kissed his cheek and walked back to the stands (this was after track practise) well i colaped in tears with my friends and he had started walking home and saw me crying and was tearing his self up over it. well that night he called me and we talked it out. the next day i cused out mckenna like he asked me to do and told her to stay the f**** away from my bf. so far she has that was last thr.. well just today i was told by a girl in his class that he flirts with a lot of girls and that he was rubbing a girl named Sidnies back last week. idk what to do... i need more then my moms oppinion on this. please help.