Ex friends boyfriend is cheating on her

Okay so this might be a lil long but ,, my ex bestfriend has this boyfriend of over a year and he’s been hurting her and cheating on her since day one but she stays well recently she head surgery and while she was getting surgery he was at school cheating on her and I found out but kept it to myself because she already thinks I’m trying to ruin her relationship. Well her boyfriend some how found out that I know and he texted me trying to fight me and he is HUGE. So basically he pulled up to my house with these big muscular females that I have never seen before trying to fight me and I’m not about to get jumped because your mad that I know that you are a cheater like fuck no & now this big ass dude is trying to fight my boyfriend because I didn’t go outside so my boyfriend is now mad at me. THIS WHOLE SITUATION IS LITERALLY SO DUMB ITS MIND BLOWING!!!