Well, it's happened only once to me so far, and we fight a lot. And the person wasn't even either of our friends. He told our mutual friend who mentioned it to someone else who then got on MSN to hate.
I think it all depends on who you choose to be friends with. His friends are very cool when I get pissy, likely because they know how stubborn my bf is. And my friends are very understanding. Our friends also know each other etc, that might help?
But at the end of the day, don't breakup because of what other people say. A good relationship always has its troubles.