I don’t hold any feelings for this man whatsoever.
I don’t currently want a child in this current world
I know he’ll be a great father.
By any chance, do you want to have a baby, but your personal circumstances aren't right and you don't feel like you should bring a child into the world because the world is a flaming pile of crap right now? I wonder if it's less about your ex having a baby and more about the injustice of how you don't feel like you can, even thought you know you'll be a great mother too.
I'm not saying have a baby or don't have a baby, I'm questioning whether you're fed up with the state of the world and this disillusionment/anger has found a way out.
5 years broken up
I’ve been in a relationship since this
he was a big part of my life
It was my first long term relationship.
You've dated since. But you haven't really had the same grand love affair again, have you? So your ex still represents idealistic love for you - even if you don't want him, you want that kind of love with someone again, and seeing him move on and tick all of the 'normal' milestones is going to hurt, not because you want them with him, but because you want them.
Incidentally, your ex owes you nothing. His status as your ex will always trump his status as your friend. He has a family now, and if his partner doesn't wan't you around because of your ex status, he'll dump you in a heartbeat, because his family takes priority. Maybe on some level you realise that, and that's been part of what's so upsetting, but even if you haven't seen that, you need to be less reliant on him.
Friends aren't aways permanent, but exes who are friends are even more likely to suddenly fall out of our lives. He might have been a big part of your life once, but you cannot keep him as such by talking to him often. It's not doing you any good.