Good luck and my prayers are with you. I would advise you to try to be as understanding as you can of her point of view, because having you world view shattered is very difficult and can take a long time to recover from. I have been married to a doc for 31 years and just found out about an "emotional affair" that went on for 15 years she is a nurse.
If we can say them together, great; if not. We have been married a mere 3. It is really hard and so good to see that I am not alone in this. But you can't make her think about the numerous facts that disprove Mormonism. I suggest to run as it will not get better. But there are many people on here who truly devoutly believed in Mormonism and broke free. But they can help. God knows the big picture. The odds are definitely not in OPs favor for something like this working for him.
Interestingly, my parents felt the same way about him. And your future kids will be taught that you are the reason they don't have an "eternal" family. If it seems one is unable to find a spouse within the church, which commandment do you keep. If they are, run to the altar, in or out of the temple. Do you see yourself marrying this person if marriage is something you are interested in for the future. An important is doing this together. I wish I had not ignored the signs whiles we dated but now I am out of energy. Sexually, risque and the such is essentially the same as baptists and fundamental Christians.
Too bad she couldn't handle the guilt and remorse. She is extremely busy and tired almost all the time. I also know that whenever exceptions are made, there are reasons. It is how she is programmed and it is a fundamental tenant of the religion. I am worried I won't be able to give him my everything, and the wonderful years of commitment and time spent with him will one day only be memories: Becoming a doctor is my dream, and I have worked incredibly hard thus far.