I have wanted to start a business for a long time and even while Andrea and I were dating it came up in conversation. Once we got married I started talking to her about the possibilities and the things we had to do to get there.
That is when I learned about the fear. I am not sure of the history but Andrea is concerned that I will quit my job and spend years broke talking about starting a business, but not actually doing anything. Even though I have never done anything like that the fear is still there.
My way around this is talk with her about it regularly, the things I am doing, and the progress I am making. That is one of the reasons I have asked her to help me in developing the website. Her part is more the idea part. I tell her what I am doing and ask her what she thinks we should be doing. I even worked with her to brainstorm the new website name and the focus.
I want to get her familiar with what is going on so she feels she understands. Plus it helps me make better decisions.
Involving your spouse is an intrical part of getting her on board mentally. Also if you can find a way to build it gradually on the side, that will probably slowly begin to give her a sense of comfort.
Growing it gradually on the side is the path I am taking.