This is such a difficult situation and my heart goes out to you and your
daughter. I wouldn't hold out much hope of your ex maintaining a
relationship with your child in the future.
It hurts and it's wrong, but he is living in the moment for himself and will most likely stay with his pregnant girlfriend until he moves on to another.
This Is A Pattern Of Behavior
There seems to be a pattern of behavior with this man and he will most likely do the same thing to his current girlfriend (and her child) that he has done to you (and your child) and the woman before you (and her child).
What is truly sad is the wake of fatherless children he is leaving behind. He is the ultimate loser in this situation and will miss out on what really matters in life and the incredible living miracle that kids can be. He is setting himself up for a life of bitterness and a bunch of kids he doesn't know and who resent him.
Be strong and move forward under the presumtion that he is out of the picture. That is what I had to do and I ended up meeting a great guy who loves my child as his own.
Good Luck my friend.