That was my experience. It's called selfishness and inability to set priorities. I know that when we have children I will be doing most of the work. Sadly, the general consensus of "convert or nope out" sounds like what will end up happening. That conversation prompted me to find and read through this sub, and there's some seriously disturbing shit here.
Unless you convert she won't marry you, plain and simple. Nobody has prepared her for one, definitely haven't prepared her for a healthy physical relationship. I love my husband so much, but 40 years of loneliness has been more than difficult. Trust me, I too tried to make it work with my very Mormon also returned missionary ex-girlfriend. Much good luck, and keep us in the loop.
Should either of you sisters raise your children and wonder what faith will they choose. And of course, everyone has a different experience. Congratulations on understanding that and avoiding problems. Note, her mind and TSCC were married first. By all means, I encourage you to try having those discussions and to make a mental note of when you would choose to walk away instead.
Life is a journey and going through it with a true partner, and a mutual respect for curiosity, is so far greatly rewarding. These are also only the American statistics. If you are a Catholic girl dating a Mormon guy, then it may not be an issue with his parents. Her Religion is the single most important thing in her life.