I think it is natural to be afraid and convert those feelings into doubt. It's hard to look at your life and say yes I know 100% that me and this man are going to be together forever. I've seen friends and relatives that had the big red flag before the wedding and I think we put money on when they were going to get divorced. There have also been those I didn't see it coming from a million miles away.
My best advice is to talk about any and every topic that you think of before marriage. You have to know what he wants to accomplish financially vs what you want. If you have someone who only cares about money and is going to work all the time and never be home but just wants to be rich.. then I would be alarmed, especially if you want someone who is going to be there for you. The FI and I play this stupid little game on date night. It's 50 questions and I'll think of something I haven't talked about before and we bring it up while drinking wine. It sounds kind of dumb but you can learn a lot about someone and be able to ask more difficult questions like about kids, house duties, what would you do if the other person passed, etc .... You both may have come from different financial backgrounds and that may dictate the way you think about money and spend it, but the most important part is if you have a similar future goal and how you want to live your life.