Since your wife is a naysayer, I’d consider reframing your approach. When you bring ideas to her, ask her ‘What needs to be true for this business idea to work?’ This refocuses the discussion around the pieces that need to be put in place for success to be achievable. If she reverts to her old habits, try refocusing her on the question above, and if she can’t get there, then at least you’ve tried to include her.

TL/DR: men and women historically have very different appetite for risk when it comes to small business ownership, and it sounds like this whole notion freaks your wife the fuck out. I’d consider having a general discussion about your goals and try to uncover what makes her so fatalistic/negative about this topic. Her dad may have been shit with money, she may not trust you, she might just be a disaster forecaster. Regardless, if you’re putting money on the line that she has a say in, you’ll want to figure out how to get aligned before diving in. Lack of shared perspective on financial risks and goals is one of the primary reasons marriages fail.