I'm currently a SAHM. Most years DP earns about $25k (runs various businesses). I honestly don't know what our FTB is.
We're fine. We consider ourselves extremely privileged. We have a mortgage and one car (9 years old). We buy pretty much what we want, but we do a lot of research on what we want and buy most things second hand. We don't spend much money on food compared to a lot of people, but eat very well.
We're happy, and living the way we want to. I struggle to think what we'd do with a higher income except pay off more of our mortgage. In fact, we had about double our usual income at one point when I was working too, and most of that went into the mortgage.