She stays home with the kids full time. Loans can get you part of the way, but we also had both worked for a several years before I started school - through no choice of mine, but it worked out for the best. Still, with maxing out your loans, it is workable. There are a number of things you might look into as far as helping out.
1) Family. They may only help with a meal out every so often, or they may help by sending a couple of hundred bucks a month. It really is not much, but it is a great help. I am not saying you should lean too strongly on your parents/inlaws, etc., and I realize some families can't afford even this - and others just won't help. So....
2) At least in the two states I have lived in during my medical school career - Missouri and Ohio - they have provisions for professional students such as medical students and law school students to be accepted for such assistance as -
a) WIC (Women, Infants and Children) - can help with some of the staple groceries, including milk, cereal, cheese, and formula.
b) Medicaid - don't knock it. It is nice to know that your family is covered and that your expense is minimal.
c) at least in Ohio, if your family makes below a certain threshold income (including loans) and your spouse either works at least 30 hours per week or takes care of your child(ren) full time, they allow for med/law students to have food stamps and/or cash assistance. Very helpful, and I know that I will put back into the system WAY MORE than I am taking out, so while it is a little embarassing and humbling, I know that it is not an abuse of the welfare system. My family really does need the help. Try raising a family of 4 on the loan money that is left over after the school and the loan company takes its cut - that is, about 17,000 per year for a family of 4 before taxes.