@MiaRebelde,
He doesn't know **** about men's opinions or women's sex lives or when they do or "should" start.
Since he says he won't marry you, then if that is what you want out of the relationship, why stay? Why not venture out into the world and find someone who won't be such a jerk about something you can never, ever change?
Your body. Your choice.
And yes, I do know he would find something else. Because finding fault for something that cannot be changed, and continuing to find fault with it, is nasty business.
By the way, did you ever wonder why he's staying with you if he thinks you're so irreparably damaged? Does he tell you what a wonderful favor he's doing you? Does he tell you no one else will ever want you (wait, he already does that, by claiming "90%" - a number he pulled out of his ass - of all men share his opinion)?
These are isolating behaviors and they are designed to tear down your self-esteem.
Hey, stay with him or not. It's no skin off my nose. Nor is it any threat to my 25-year marriage.