I find that having zero expectations, single parenting and having my own life makes our marriage work well. Other guys I've dated in a similar situation have just asked me to put the keys in the mailbox when I leave though. Early in our relationship, I gave some thought to the question of whether I would ever be willing to marry a non-Mormon. That being said, no matter what the cause, I wasn't getting what I needed out of it and I had to make the decision to either keep things the status quo or move on. As Joanne mentioned, should you marry interfaith, you will have lots of help from fellow ward members on converting your spouse. The important things that keep our marriage a happy, healthy, and very loving one are the same things that keep any other marriage alive and well.
I dated non mormon men. However, for me, there have been some perks too. It really has been helpful. I love my former Mormon friends and family, but a relationship requires devotion and trust and understanding. Right now she won't even watch a movie. She asked me the other night how it's possible for me to be such a good person when I don't believe in god. Doesn't leave many options here though but better than constantly having them push the church on you until you either give in and convert or break up.
I felt her fear, everything she's said, I said. I mean lots of his friends from residency have girlfriends or wives and make it work. I knew a woman who married a man who converted to the church and she spent the rest of their married life telling him he was not good enough. Be specific every time you ask. However, for me, there have been some perks too. This makes them overwhelmingly successful wives and mothers. We can also save our errant children by our valiancy too. Her beliefs are innocous but ultimately a death sentence for this relationship. I'm a nevermo, but I married a then TBM girl, so maybe my perspective will be of help to you. Listen to the still small voiceв.
Ask questions, try to find out as much as you can. I look at my single male doctor colleagues and some of them are sweet and honestly looking for a connection. Her goal is to make you mormon. She converts to your religion.