(I AM A GIRL BY THE WAY)
Most Helpful Guy
Some people do that and its hard. He will miss u both but he has replaced it with somebody in the same situation as you (same looks age and a young child) he's made a poor excuse to leave and moved on quickly, which is wrong. You need to forget him and be there for your child however difficult it is, your child needs u more than u need this guy. In time he may regret what he's done but you would be foolish to go through it again. By putting his new life on Facebook he is hurting u more so delete him and don't look at what he is doing just be there for your child, as he will be confused by it all too. Do things with him to take his mind off it and explain to him in the future when he can understand more.
Most Helpful Girl
He's a total wanker. Really sucks about the kid but the only thing I can suggest is making sure he pays his share for the baby. I wouldn't let him get away with that.