Is your husband stay at home, or the primary caregiver?
My husband would be open to another child (although, he is not yearning,) but I do NOT want one. I stay at home, so he left the decision up to me. While he wouldn't mind another, he respects the fact that I am around my son from the time I wake up, from the time I go to bed. I see my child and care for him over twice the amount of time my husband does. Plus, by the time he gets home...all the caring, cooking, cleaning, disciplining, and tasks are taken care of. It's basically play time with dad. He is a WONDERFUL father, but lets be real. He gets the easy part. He understands this. He knows the stress won't fall on him.
Has your husband told you WHY he doesn't want another child? I have communicated very openly why I don't, and my husband with me. Even if he's not the primary care giver, when one person is dead set against...there is nothing you can do about it...but accept it. He has to have reasons, and you have to be willing to hear them. Perhaps, you should take a break from talking about it a few months and revisit the conversation. If he still doesn't want more, focus on the blessings you DO have...not the ones you don't.