Is this normal?

I hate when my SO goes down on me not because I'm uncomfortable with it or anything but because I don't feel any sort of pleasure while he's down there and I've told him that before and he's tried everything there is to try to get me to feel something but I just end up feeling gross cause his mouth is all over my lady bits and it doesn't feel good. I don't think he's doing anything wrong and I don't really know what would make me numb enough down there to make me not feel anything I've had other guys go down on me too when my SO and I weren't together and I never got any feeling from them either