I agree, that word sucks. He shouldn't have called you that, BUT I also think you shouldn't have punched him.
There's no excuse for violence against the one you love. It doesn't matter how pissed you are. Yell all you want but physical violence is crossing a big line.
I was punched by a boyfriend once and it was the last time he ever got to talk to me or see me in person. I just couldn't feel safe with someone who would do that. I have issues with anger as well as REALLY bad PMS. I take up extra exercise when Aunt Flo is visiting. A walk/run outside can get your heart rate and endorphins up as well as give you space whenever you need to cool your temper down.
Fights happen, but we should always strive to be in some sort of control so we don't do something really out of line.