Man. Do NOT feel bad. What were you supposed to do, keep letting it go on, let your best friend marry this cheating bitch, and let your brother continue to bang your best friend's wife? Please. That's just not on. That would have made YOU a piece of shit, which you totally are NOT.
I'd like to hope that my friends are like you, dude. I'd like to hope that my little brothers are like you. What you did was commendable, don't let anyone tell you otherwise. Yeah, it got ugly, but I think you handled things as well as could be expected. You gave her the option of being a woman and breaking it to her fiance herself, and did she do it? Hell no. If anything, she has culpability in the fact that your brother got his ass beat, as she could have prevented that by being a decent person and doing it herself! I can't believe your brother tried to make up some fucking excuse, gods, he's also responsible for the fact he got beat the fuck down on top of the fact that he was fucking her!
If anything, I would have been tempted to let it go on. I'm sure you did the right thing, pulling your best friend off him before something really bad happened, like his death, or cracking his skull or winding up paralyzed or something. There's a good chance I would have just sat there...you're a better man than I! Or perhaps just less vindictive lol. I've been cheated on before by someone I had plans to marry, so maybe I'm a bit biased by that fact.
Your brother CONTINUES to be an utter bitch by the fact that he's trying to press charges. Can't take responsibility for the fact he was fucking an engaged woman for eight goddamn months, can't man up to the fact that you had to be a human being with an actual heart by not being able to stand for what was going on, can't be a man and take a beating he WELL deserved, and runs to the cops like a cunt when he can't defend himself from the guy whose lady he was fucking. I mean, come the fuck on, he expected to not get hit for fucking someone's goddamn FIANCE, or all things? They say some guys think with their dicks but that takes the cake. I cannot.
Shit, I'd go make a deposition to the police about what went down, and if they try to pull you into court, go and testify! Make for damn sure your best friend asks for a jury trial, if it comes to that..no jury in their right minds would convict your friend with what happened to him!
Stick by your best friend, but your brother needs to man the fuck up, and someone should still kick that bitch in the pussy. I swear....