Well, we aren't in that position anymore but we were. My husband has his own business and when my DD was born in Oct. '08 the markets were totally collapsing. He lost 40% of his income.
I have DOR and was 37 years old. We knew if we wanted a sib for our DD we had to go for it. We were fortunate that insurance covered a lot but I dropped to 3 days a week at work when I had DD and with DH losing so much income it was very, very tough.
We were blessed with twins

and they were born in the midst of the great recession when DD was 16 months old. Financially, our lives were a disaster. We are both educated people with good jobs and the fact that we couldn't support our family kind of blew our minds. We never bought cribs for the twins. We had no space and no money. Very tough times.
I am happy to say that things have improved dramatically for us. My husband's business is soaring and he is making far more than he ever did before. But, the stress of having 3 children in 16 months and dealing with the greatest financial hurdles of our lives have left scars on our marriage. To be perfectly honest, we have a long way to go before we will be back to a truly healthy relationship but I do feel that we'll get there.
So, the "moral" of my story

-- if there is one -- is that you have the rest of your life to make money but only a small amount of time to make your family. But, don't underestimate what financial strain can do to a marriage. My marriage was very, very strong and if it weren't I don't think we would've survived the last year.
All the best to you!!!