My SO called me "dirty bitch"...in bed.

My SO NEVER calls me names. And we both love talking dirty in bed. But today we were bding and he asked if I wanted him to talk dirty to me. Of course I said yes!😍 He then called me "such a dirty bitch" multiple times. Idk why but I feel kind of offended by it. Should I chalk it up to him just trying to spice things up or should I go with my gut and feel that it's not ok?