I would try to find some shared vision of how real estate investing can improve your lives together, as a couple. Sounds like she isn't highly motivated by money, because she feels comfortable right now. Maybe share with her how having your own real estate business puts you guys *in control* of the money, versus relying on an employer to keep paying you? Or what about the security of having an income that doesn't require you to put in as many hours, as you start to get older and not have the energy to put in long work weeks at someone else's business?
In any case, don't push too hard, as others have mentioned, because you don't want to create resentment. I'd work the "you catch more flies with honey than vinegar" angle of luring her into the business by making your excitement and vision contagious.
And if that doesn't work, just accept that this is YOUR passion and you will just have to make the most of it without a partner. Many, many people do this as single folks, so don't let the lack of an involved spouse hold you back.
Best wishes!