Future Marriage Ruined

So my fiancé and I got engaged back in February after dating for 5 years, we had to postpone everything due to the COVID. We were going to get married through the Catholic Church but now he doesn’t want to do that because he’s questioning his faith and basically wants me to change my views and beliefs with him. He no longer wants to get married through church and now he wants to stop having sex until we get married because that’s what the Bible says we should do. Because I am disagreeing with him he says I have “brain damage” and is calling me “dramatic” because I am fearing I could lose him because of this. What should I do? I’m so confused.