Man...here's my view and call me off point or whatever, but here it goes. If you and this girl are at the level to where yall are comminted and in love, you shouldn't have to trip off other peoples attempts at getting with her. A female is not some weak creature who can't make up her own mind, and she can tell the other cats, point black nah I have a boyfriend. If they hate after that then they deserve to get snaked or whatever, but how are you gonna get mad at the man for trying? If you just turn around and smash on dude after you heard he was spittin, what are you gonna get outta that? Just the satisfaction of whoopin somebody's ass, basically. But if they are your real homies in the first place, they wont holler at you MAIN girl. At least not if they know how you feel about her, unless they just have no respect for you. That's the case where I would put somebody in check, but I still wouldn't cross him unless he came at me wrong when I confronted him.
But I'm the type of man who will leave it to my girl make the decisions. If she wants to go be with dude after he runs his little game, than so be it, you aint worth my time anyway. Don't let the door hit you on the way out. I've never been in love, so I can't say how I'd react if somebody got at a girl I loved, but just saying "I'd smash" makes you look like you have no confidence. But of course, what many of you call "homies" aint shit but some sheisty cats tryin to get over on you. If your "homie" knows how you feel about a girl and then tries to fuck, well be mad. You should. But I wouldn't smash, I'd tell him to check nuts and that would be the end. If he doesn't know how you feel, then tell him, and if he is respectful he aint gone say nothin.