Bf and bestfriend drama!?!?

Okay, my bf Tommy says he loves me.....I love him.....duh!So my (Ex)bestfriend Kayli and him started talking I was cool with it....Now 2 weeks later yesterday and still today me and Tommy are in a fight.....She starts saying a ton of **** like : not my fualt he loves me more than you , I want to hit you, Your a *****! Crap like that! So I say **** back.Now you would think Tommy would stick up for me.....No he doesn't ! Yesterday he broke up with me and then went back out with me after he thought about it and I cryed my eyes out.All Kayli had to say was im sorry! I was so pissed.SO now i told KAyli and Tommy She hits me im going to hit her right back.All he says is if you do then its ******* over! And i was like if thats what you want.......Now he is pissed at me for his ugly *** resons.Im going to hit kayli tommrow and idfc what he says ! Now he and her like each other and will txt for hours and he ignores me and txt her and i know they are txt cuz he tells me about it! I want to brake up with him but I don't.And for Kayli shes dead......Please help!