Good luck on getting your wife to change her mind. If I want a good fight all I have to do is mention living aboard.
My wife is like a kid in a candy store when we are out sailing and loves every minute of it. Some time she sits up on the bow and is in another world. Live aboard and her answer is I can and come visit her on land.
One day she came home from work and told me that we should take off and go sailing for a couple of months. I should have jumped at this but I told her that we could sail all summer long if she wanted.
To me it doesn't make since that she doesn't want to live aboard. We live in a 40' RV what's the difference. She has to have that land locked nest.
Your wife needs that land locked nest. She wants to take the kids to the park. Have them is school and all those activities for them. She needs her girlie girl time with her friends. As she sees it all that would be gone if she lives aboard.
If I were you I would just day sail and weekend with the family then after the kids are grown then bring it up again. The more you push it the more she will back away. Let her come into in her own time.