Gonna be blunt op, at 40 you should probably start thinking about other things. I mean, yes, it could still happen but really, why let the desire for it override all the other good stuff in life?
Maybe he was not the right man for you. But if I was truly happy wit him then I wouldn't have left him over bullshit broodiness over a hypothetical, non existent child.
You may have been right to leave him as his tooing and fro-ing wasted your time though and this may have been a manipulation all along but please don't reduce your life to your ability or lack there of to have kids. There are far more things in life to experience.
Also, presumably youll need a year or so meet someone new and another two years minimum of knowing them before you would have kids...and that's only if that relationship gets that far, otherwise you'll be back to square one...
I just hope you left for you. And now because you thought it was your only chance for more kids.
Again, not saying it can't happen but...
Also, you'll have to be extra careful about picking men now because your broodiness may make you settle for the wrong man. And then, boom, life down the swanny.
Just, put the kid thing asside, seriously.
Find a different path and different dreams.
You never know, it may still happen but you shouldn't govern the rest of your life based around it.