My husband isn't 100% on board either. He's concerned about our personal assets and doesn't want to divert money that he thinks should go into our retirement accounts.
Our compromise is this: we agreed that if I earn money from consulting outside of my regular job, that can go toward real estate investing (my W-2 income is all accounted for in our family budget).
I'm positive that once I start and he sees how it works, he'll get interested in the number-crunching and realize how much better real estate can be as an investment tool than sticking all our money into a 401k. Not saying we'll quit doing that entirely, but that this is my plan to bring him 'round.
I'm also developing a really super-detailed spreadsheet that combines the best of several downloads from BP, and am going to ask him to review it and show him how to put sample purchases in. The thirty-year forecast alone should show him the benefits of REI and leveraging.