Go for the joy, the experiences, the children to come. I'd love to hear from more veterans about how to make this work in the long run. Work on myself, not him. I also think that if marriage outside the covenant is a sin, it is not so grave as to be unforgivable. Without going into too much personal detail, I received a very real, strong prompting that I should marry this girl. Is forever possible with a doctor??. If it is even possible, would it strengthen or weaken their ability to develop a personal relationship with their Heavenly Father.
Don't expect a traditional marriage I am sorry for your story. But there are many people on here who truly devoutly believed in Mormonism and broke free. This can make it harder for you two to do things together. If you can, do it now. These girls are nervous around non-Mormons. I've been thinking more about your situation and another thing came to mind. For now, again, don't expect a decade long relationship. If you aren't sealed together, say good-bye for eternity. And, whether she knows it or not she probably does know it but is in denialshe probably sees you as her ticket out of Oldmaidsville.
Some great ideas include going on a hike or a walk, having a picnic outside or going to museum. With me it's less about taking my time and more about the mental drain. My beliefs have changed several times in my life, but not those things, so my interfaith marriage has lasted 25 years. That would only encourage her to give up other standards that really are serious and to become like the typical Western degenerate.
Learn more about the LDS Church. Just talk to her honestly, and if you have to, use the old wonder of logic. Even if the church believes a bunch of crazy nonsense, and she believes it too, I still really like her and would like to see whether we can have some good intellectual conversations about this stuff. I am totally okay with anything that doesn't place physical or mental demands on me. There are many catholic families with these three main ethnic groups within it.