This is BIG BIG BIG deal. My Aunt and (favorite ever in the universe) Uncle were getting divorced over this issue when he was killed (not by her). It actually isn't an uncommon issue at the divorce table.
I would take a week and seriously think about all the angles from YOUR point of view for at least a week. Think obsessively. Would you be happy never having another baby? Is it "A" baby, or HIS baby that you want? Is it a baby v siblings for your first? What if your soon-to-be was in a car accident or radiation treatment and could never have any more children (please god, in that scenario, lets assume the rest is undamaged), would you still want more? What if you had to wait five years or ten?...how do you perceive you'd feel about waiting?
ETC, ad nauseum.
Once you have all the answers that are true to your own heart, talk with him. If you are still at logger-heads, I would think some more...and then see a counselor and as many trusted friends as I had.
The idea of future children can be an absolute for some people. It can destroy happiness, if not the actual marriage. I've seen people (friends) get past it, at least temporarilly...ask me again in 10 years. I've seen people (in my family) come to divorce over it. It's a big deal, and deserves to be treated as one.
When you say "move on & deal with it" does that mean coming around to his point of view? Or does that mean getting past his hurdles until he is at your point of view?
Unfortunately (or fortunately, depending on your point of view), these are all questions only you can answer. The upside, of course, is that I find once I have answered all my questions I replace torment with a happy, secure sense of...well...whatever. :)
I will say I'm in the opposite boat right now...my husband has decided that he wants more children since he "missed out" on our son. Nope. Sorry. Not going to deal with cancer treatment again(i get hormone driven cancer when pregnant) because you decided to only be home maybe 6 hours a week for 5 years. Oddly enough, at one time I wanted anywhere between two and nine kids (preferably multiple births)...i know, I'm nuts...and he only wanted one. Now I'm reeeeeaally happy with just our one. BUT ..and here is where personal sharing relates...a large part of it has to do with the fact that my husband isn't a family kind of guy. He doesn't love kids, laugh with them, play with them, dote on their mamas...he wants alone time. Some of what YOUR husband COULD be feeling in addition to the economy, wedding stress etc, COULD be him putting you in his exes shoes. If he essentailly raised his seven year old on his own, he might not want to do that again. Or he could be afraid of either or both of your kids feeling supplanted by the "real" child. Hate that term, but kids invent it because it happens.
Anyhow, lots of issues, lots of questions. Good luck in finding the best answers to yours, and peace and happiness in those answers!!