So perhaps the question shouldn't be about what does a non-programmer bring to a small team, but rather what do you as current co-founders not personally bring to your own business?
If building a scalable money making app/service/product/thing is what you want to do, then customer development is going to be just as important as product development, and connecting the dots between customers/users and your idea/features cannot be written with code alone.
Either the existing co-founders will need to share an equal level of interest/skill/time for the other parts of the equation (design/ux/sales/marketing/support/bizdev/funding/everything else), or you will need to acquire these skills via payroll or equity.
Knowing in which areas you suck will help this process a lot, and this only comes with giving something a go yourself.
Once you know your weaknesses you will be in a good position to assess what skills/experience a new co-founder will need to have to balance things out.