He might be too big advice?

We have been together for a while and he has always been big but every once in a while he is like too long (I meant literally his length varies between like 7 and 9 depending o nthe day how many rounds etc) and if he goes all the way inside its way over stimulating and hurts he always feels bad and stops and I've even cried cause he hit my cervix or whatever wall is down there any tips from other girls in similar boats? (being high has worked and even made it feel much better but we can't be high every time) h