My husband is obsessed with anal...

So my husband and I have been married for 5 years now. Two years ago we did anal for the first time and it was an every once in a blue moon thing because I honestly am not really into it, but I was willing to do this for him every once in a while bc he really likes it. Fast forward two years and it’s all he wants!Every time we have sex he’s asking if he can finish in my ass or has to have a finger up my ass to cum. It has become such a turn off for me. I dread having sex now because I know he’ll ask and I’m just not into it. When I bring it up to him he says he just doesn’t understand what the big deal is, that it’s something he really enjoys and why can’t I just do this to make him happy...

Advice please!!