Nipple sucking

So I’m currently approaching 37 weeks in my pregnancy and I have not had any desire to allow my partner to suck or lick my nipples. I feel kinda bad because he loves doing it and I feel like I’m just always rejecting him but it just doesn’t turn me on anymore at all. It actually makes me feel weird and way to sensitive. I always let him do it before and I have pretty large breasts and he loves it so much. Any advice or ideas as to why I suddenly hate my nipples being sucked?