Get yourself into therapy asap.
You have wasted time with a man who changed his mind.
Be very very careful of thinking your love for him will outlive this disappointment.
I don't think it necessarily will if you really do want another child.
I know of a couple of cases where in one the wife got over it, embraced having one child and was able to move on successfully.
The other where the relationship broke down and she had a second baby on her own at 44, by IVF.
She never regretted it and because of her good career she has had a good life and met someone else, but has never lived with him.
Interestingly her ex husband met someone else too and had one more child and is a one night EOW father to his first son.🙄
Look very hard at what you really want.
I think the vasectomy suggestion is excellent whilst refusing being responsible for contraception.
I certainly wouldn't remain in love with someone who would change his mind on such a core issue.