Saying my child was not his

Years ago before I had my rainbow baby I had a miscarriage. I didn't know I was pregnant. I was having my monthly menstrual cycle, but I did find it odd I was bleeding more than usual. Fast foward 3 months later at the hospital I find out I am having a miscarriage because daily my hcG's were decreasing daily.

Fast foward years later...after having my rainbow baby. Whenever my fiance (still considering if I want to call it off) gets mad he tells me my miscarried child was not his and calls me multiple names for example: whore, slut, bitch. Once he calms down he apologizes and says he knows it was his and he can't control himself when he is angry. But when we gets angry, he does it again. Every single time. It hurts me he is constantly bringing up a baby that has no part in our discussion. Keep him/her out.