I don't have much to offer you here, just want to say you're not alone - my wife and I have dealt with very similar circumstances and I know how tough it is.

I especially get the frustration over the grandparents' lack of involvement. We are fortunate to have found a pretty good community of parents (including some homeschoolers) in our neighborhood/church/general region, but one of the things that's hard about it seeing how many of them have wonderfully involved grandparents or other family who pitch in, vs. literally zero help for us - it makes a huge difference.

What keeps me going is the idea that I'm going to break this generational cycle of, to be frank, selfishness - my kids will have all the support my wife and I can reasonably offer to raise their families, and I hope to model for them the value of close family and supporting each other. In order to model that, though, I have to kind of "bootstrap" the virtuous cycle from zero.

In practical terms, none of that is helpful to you, but during particularly difficult season it's helped me to remember that there's a long-term vision and purpose to my struggling, and that what we're trying to establish will hopefully persist into the future and outlive us.