That’s all good news op. No of course it’s not the same as planning the baby together. But you can still make it amazing and wonderful without him.
I agree with @Dontknownow86 . Tell your ex that you will let him know once the baby is born. Then stop all contact with him and make sure that any mutual friends don’t tell him anything.
Make all your birth plans with your friends and family. Once you are home from hospital, go and register your babies birth with your choice of first name and your surname. Put in your claim for child support online .
Then contact him with a photo and details of the baby and let him come and see baby.
You will get over him a lot sooner if you do this. Do not I repeat NOT send him baby info in the hope of luring him back.no scan photos etc . It’s YOUR PRIVATE MEDICAL INFO. Don’t sent it to him and then complain it’s all over Facebook etc
Anyway It won’t work. He might make promises because he feels guilty , then he will let you down again and you will feel ever worse.
Believe him when he says it’s over and plan your best life without him, except in a very minor role. Most men in his siutauon do not have the baby 50:50, so ignore any MRA who come along and tell you this.
Odds are that he will see very little of your baby and that will fade out after a few months or certainly years. That’s the sad reality I’m afraid.
You have ZERO responsibility to make him see his child . You will have enough to do being a single mum and working FT I promise you.
If he chooses to see his child you need to allow reasonable access, but their interest usually wears off.
Your only responsibility is to yourself - your physical and mental health and that of your baby. So ignore him and this girl and look after yourself