Have you and dh sat down and figured out what you don't need to be a SAHM? I mean, what does it cost you to work? Do you have 2 cars? How much do you spend on good clothing and assessories? Do you bag lunch or buy lunch? Are you in debt? Add all your working expenses and subtract that from your income. This will give your true income.
These are the things that helped us so I could be at home with ds. The first thing we did was eliminate credit card and loan debt. That was the big one. Over time we have downsized on different things to make it easier. We now run on one good car. We do have a car payment, but we didn't buy new and we have extended warranties so we don't have to worry about costly maintainance repairs. Our other car was paid for but it cost us a small fortune because everything kept breaking down. One car means one insurance premium, one tank to fill, and one car to maintain. The insurance saves us $600/year, we have cut down our gas consumption so we only use one tank every two weeks and that has saved us over $80/month. DS has playgroup on Wednesday and Thursdays, every second Friday I like to go to the market. I drive dh to work on those days and pick him up after. It's really not a big deal or a hastle. It has also helped me to consolidate my errands which also helps with the gas issue. We actually make it a fun day. We take dh to work and then I take the kids for bagels before dropping them off at school. The kids love the treat.