You know damned well why you got the baby fever.
Got a new guy you are settled with and you want to make a kid with him before it is too late. Right? It's a pretty primal thing. Pretty normal too. I know 60 year olds with bad cases of baby fever for precisely that reason.
I am gonna tell you straight.
You have already made the decision.
You can't have another kid right now, and you need the surgery. He has said he doesn't want more and you have no reason to assume he is lying.
Sometimes it is kinder not to tell the guy. Baby fever we sort of understand - guys get it too, after all - but it is something we simply can't help you with (apart from in the obvious way).
Are you getting a hysterectomy for medical reasons or just to not have any more kids? If not for medical reasons, you can consider an IUD instead. Copper ones last up to 10 years in place and hormonal ones 5. If you and your partner decide to have kids in the future, then you just ask your doctor to remove it and done ;)