Why does my boyfriend always refer to women as b*tches?

I've asked him to stop numerous times but he never does. Doesnt matter what were talking about he'll always use the word b*tch or whore when we're talking about a female. My boyfriend seems to have this deep hate for women that I just don't understand. With all that being said he has never called me a ***** a to my face. However we had a huge argument and were texting back and forth and I said some really mean hurtful things to him that I apologized about later on and he called me a b*tch. But never to my face has he called me a ***** or been violent towards me in any way. When we argue he's usually the calm one....I don't get it. What's his problem? Will he eventually become violent towards me and why can't he not use the word b*tch we refering to a female?