Friendship over soulmate ?

me & my boyfriend been together for a while. August 27th will be our aniv. My friend introduced me to him. They're like bro & sis. But now. Things changed. They're at neck&neck wit eachother. Bumpin heads & what not. Idk how to handle this. It's gettin way outta hand now. They are fightin. Not jus wit words. I want them to be cool again. It's too stressful for me. Do I jus cut them both off? Or try to get em back like bro & sis. Do you think it'll help if I say " yall either get yaa acts together or I'm gone. " it's like they're out to kill each other jus bcuz my friend broke one of my boyfriend's promise! My boyfriend is the one puttin his hands on her & sayin **** to bring her down. Well that's what I heard. I've seen a side that I've never thought to see come outta him. Out of all ppl.. Not him. I don't wanna let niether of em go. But I gotta start thinkin bout myself. Put myself first for once. It's stressin me the hell out. So. What do yall have to say? All honest answers please. I'd appreciate it so much. Thanks.