D.,
I can imagine the stress you're dealing with trying to think of how to make this all work. Take a deep breath and relax. ;)
Have you sat down with your husband to determine exactly what your expenses are? There are so many little changes you could make to help lessen the burden of many of the basic bills. It may or may not be entirely possible to be able to stay home. Your husband seems in favor of it, and I have found that husbands like that will do what they can to make it happen. Be proud of him for wanting to allow yo the luxury of being there for your little ones as they grow up.
This sounds like something you'll need to tackle now in order to get a good strong hold on your finances before you have to take that maternity leave. If you have a financial adviser, sit down with them and see what kind of manipulating can be done. If not, maybe asking around at church or among your friends to see if you can find one might be worth it.
You can also consider any work related skills you may have that might allow you to find a work from home opportunity.
I would be happy to offer you many suggestions, if you'd like. I have been a stay home mom since I was relieved of my job 4 months before my first child was born, while my husband was already on unemployment. We have since moved twice and my husband has changed jobs 3 times (looking for another change shortly). In that time he has had many extra jobs as well to make sure we always have what we need, and I have never returned to work outside of the occasional pizza delivery job for personal sanity... LOL! It can be done.
Wishing you the best!
Blessings,
Rolinda
Wife, Mother, Friend