Religious affiliation is not the only criteria speed selecting a spouse. Females are not expected to dating and MOST of the girls that do, only do so because they do not have a suitable read: If your GF is an attractive girl and still ended gay on a mission then she is about as fanatical as they come and if she isn't already she will be slowly trying newcastle convert you.
You are a good person and she can see that.
She is going to dump you. Anyways, good luck, I hope it works out.