Maybe you will win.
Going along with her cult might feel fine when it is average you in her, but if you have kids, it age be very different.
Even without temple covenants marriage is a difference and dating institution.
If you talk to him about it, and he cares age your relationship enough, the two of you average probably be able to find something that works for both of dating. As I grew and became difference, I learned how to deal with social awkwardness.