Cm and sex pain

I've noticed with my CM when it's heavy I tend to not have good sex. It hurts when we start and halfway through, my vagina just stops feeling anything. My clitoris doesn't feel anything as well. So I'm really confused.. I would like to have better experiences with my partner but when this happens he's disappointed as well as I am because it is almost impossible for me to be pleased. Since I first had sex it has always been hard for me to pleasure right but this makes it impossible..