Perhaps he wasn't lying. Perhaps he was trying to come around to the idea but just couldn't get there.
I also have to throw out the idea that this issue is pretty much a moot point anyway. You say that at 40 a pregnancy would be a miracle - and you're right. The odds are very low. Have you realised that you are arguing over something which may not be possible anyway?
Never regret anything that has happened in your life. It cannot be changed, forgotten or undone. So, take it as a lesson learned and move on.