Reading all your comments makes me feel sometimes uplifted, other times scared as hell. He is controlled by his pediatric physician wife, trying to help others with their illness, and still is with me. I went to BYU.
Know her limits on substances. Secondly, if he's still in residency, he has to prevail and give it his all. Oh well, I'll just pretend she's not mormon and see what happens. Plan on knowing their religion better than they do at all times. I've read through some stuff there and it all seems pretty tame so far. I didn't hear from him all day, is that normal.
But what if your girlfriend is Mormon, but not active in the Church. Cold approaches on Mormon girls are challenging. Might be worth working through the missionary lessons and CES letter to see if they can agree at least to disagree. She might not be keeping the Word of Wisdom, living according to the Law of Chastity, or attending church regularly. So when our children bring home a potential mate that has cultural, racial, religious or other big differences then our child, our concerns immediately flare up. A good man is not defined by his religion and a great marriage is not defined by where it takes place. We Finally spent a week alone together for our anniversary and it was glorious. I am not sorry I married outside the LDS faith. I mean, there was no way it could be worse than intern year. But now he is a senior doc and is called on for all the difficult stuff and can't or won't say no.
If she is as real deal as you say she is, she believes this also. Fortunately most of my immediate family has done better. Anecdotes vs a much larger sample size. One small thing to add here. What do you think is a reasonable expectation for how much time you will spend together, how often you will talk, etc. You should be fine as long as you stick to the lines you have laid out. Who knows, but I think it was especially hard for the moms of young men.