I bought my bus about 7 months before I broke it out to the little lady. I hid it at a local rv storage (two blocks from the house) for months, and snuck away to work on it when I could. When I finally told her (and she dosn't swear often) she asked "are you a F****ng idiot? Then she would'nt let me bring it home. I finally did, and worked on it throughout the summer, and got a lot of the interior done. When she finally came out and looked at it, inside and out, she started warming up to the idea. Now she is involved with the color and decorating aspect. She says most of it is built for a man, but she can live with it.
Some things I stressed were:
* I'm at home working on a project, not drinking in a bar everynight and coming home to slap the family around.
* We both have hobbies that each of us enjoy and alot money monthly for those hobbies. This is mine for now.
* The difference in safety and cost between a self converted bus (That is done right) and a 150,000 plus class A
* We both require time alone now and again. I can do this, still be productive and be right out the back door.
* I could sit on my nuts, watch TV and ask for you to get me another cold one. Instead I'm doing something creative. Though I still ask her to get me another cold one
* It will give me a warm place to sleep in case I'm ever in the "Dog House"
*You fill in your own specifics.
I would say conversation is an important key. Good luck with your venture and hope she comes around, or at least let's you finish the build and drive it around. Maybe she'll get curious enough to come along and maybe enjoy it.