I agree it’s time to move on – forward, not back. You want different things. Unmarried men don’t typically go finding out their ability to have children. I would absolutely be suspicious that he was trying to baby trap you – “miracle” or “opportunity” or some similar approach.
He wants children but he doesn’t want to be the primary parent. And that approach to parenting is not what you want. And that’s OK – but you should not have children with this person because they want you to take on the majority of effort. And while I don’t want to assume your partner is manipulative, I suspect that they are thinking “well, once she gets pregnant/has the baby she’ll never want to leave its side and she’ll be fine staying home.” which you’ve said is not what you want. Your partner is assuming future you will be completely different from what you are saying now. Does he ignore your words and assume he knows you better than you know yourself in other ways?
I’m sorry that you’re dealing with the end of your relationship, but I think you have wanted two different lives for some time. Now that you’ve arrived at this fork in the road – I think you have to take separate paths.