My husband not only supports me going to church he encourages it because he knows that it is a part of me and makes me happy. See if you can become involved only if it follows your strengths and desires. You can't gamble on her seeing Mormonism for the shit show that it is. Just going to jump in and then jump out I remember how idealistic I was back then, but here's reality: You will be without him most of the time. She got engaged 3 months later. Marriage is simply not an option to me there. Sorry you had to go through this, but it's for the best if she's about to leave on a mission. Even without temple covenants marriage is a noble and worthy institution.
Would I like to have him by my side. I know you got a zillion replies, and I have not read them. I'm surprised you don't seem to know how long his residency will last. I am fortunate to be married to a surgeon who, although he has "the ego," he maintains Christian values in our home.
You are too young to deal with this. If you think your girlfriend's resistance to being exposed to anything critical of Mormonism sounds cult-like, you are right. There are two ways to go about this. Be a good influence. I met my wife at the age of She literally showed up at my apartment one night, wholly unexpected. I understand in some measure of the pressure on the provider, but this profession was their choice.
She is probably thinking she can convert you if she is with you long enough and is a good enough example. I love my former Mormon friends and family, but a relationship requires devotion and trust and understanding. It is highly likely that she will pressure you to convert, and if you resist, she may resent you for being the barrier to her being sealed to her children.