I think you're doing what I did to an ex CandyCrush.
You don't love him any more, but you do have very strong, conflicting feelings - happiness, sadness, regret, what ifs, anger. You haven't let go of any of those feelings, even after all this time.
You were pleased that you 'beat him' by getting into another serious relationship first. You were winning, with the marriage, and had expected to keep winning by delivering a child first too. You've convinced yourself that you are over him, but you're not. Yes, you don't love him, but there is much more than love to get over after a relationship breaks down. Its like living a traditionally successful life after him proves how much of a better person you are.
Now your 'be the most successful plan' has been thwarted, by him 'beating you' to having a kid, you're in flux. He now has an important life after you, just like you do, and you aren't handling that well.
Trust me, I've been here. You want nothing good/happy to ever come to your bastard ex, because you believe he doesn't deserve to be happy ever again. Because you are so angry at the way your life together has turned out, and the injustices you feel he has done to you.
When really, the healthy way to be is to have complete indifference to whatever he does.
I suggest counselling to help you get there. I really changed things for me.
Best of luck 