Damn… I feel for you. It sounds like you are in a tough spot. There’s lots of good advice on this page, and the one thing I will add is to protect and keep working on your relationship. Money is the core component of many (or was it most?) relationship problems.
You can get through it, but (IMHO) you need your wife right there with you (or at least, I did). We were doing ok until I tried to start a business and dropped my 9-5 job. Revenue was slim, and then at one point I earned nothing for 6 months. We were on the bones of our arse - living off a meagre kindergarten teacher’s wage paying rent and food. Without my wife, we would have drowned. She did amazing things in budgeting down to the last penny, no luxuries, riding everywhere, spending time together. It was hard and there was no end in sight for a long time. We were very lucky and things turned around. But I would have not managed it without her (and her incredible budgets).
It sound like you have been deep in it for longer than we were, and I wish you all the best in working your way out.