Brutally, yes, you do have to end it - or try somehow to curb your desire to have HIS child.
He doesn't want another child. You didn't want children before and don't know if you would again with someone else. Having a child with him is therefore not an option.
How would you feel knowing that you would never have a child with him? Would it be worse having no child, or would it be worse losing him?
I mean, you can't know what it would be like to have a child because you've not done that. So it's something you're missing, but an abstract ideal, really. Whereas you know how you feel about him and your relationship, that's not abstract, that's reality.
Would you really throw reality away for an abstract ideal?
On the other hand, if you're going to resent him not wanting another child then your relationship is doomed anyway, so you might as well break it off while there's no acrimony, save yourself years of bitterness. Also, that would give you the chance to see if there was another "love of your life" out there, with whom you might also wish to procreate, who would want a child with you.
You don't have long to decide so you're going to have to bite the bullet, make the tough decisions and then just do it.