Was this in the US? From what I'm seeing it seems that making fun of stuttering is the norm there. That is so disturbing to here because from my experience Americans are very talkative and friendly. Over here in Europe I can't even remember a time somebody making fun of my stutter, at least to my face. Back to the matter, I really hope your boyfriend did stand up to his friends about this. They seem to be awful. Please don't punish yourself for others being morons, if you do that you let the bullies win.