why does he want anal so bad?!

My husband will not leave me alone about anal he just constantly tries to go there during sex and keeps telling me he'll eventually wear me down. I don't want to have anal. We've tried and I hate it. I'm open to a lot in the bedroom but this... I can't do! 
So how am I suppose to have sex with him if he's trying to violate me in places I don't want?