There is an entire universe of feelings that women go through related to their reproductive systems that men cannot even begin to fathom, and I certainly won't pretend to here. (I'm just hoping I get credit for knowing that I can never know.)
I don't think you should try to change your body any more to accommodate the birth control notions of your husband. More importantly, the two of you should sit down and come to an agreement on the simple question of whether you want more children. That one issue alone could easily tear things apart if you're not careful.
If you two do decide you don't want any more kids, I'd highly recommend him getting a vasectomy. I got one (very) shortly after our third (and last) son was born, and I'd be happy to chat with him if he has any questions.