pregnancy alone? the father doesn't love me anymore...

Serene
Hey guys, this is a quick run down of my story, I met a man early this year, we fell in love pretty quick, 2 months in we accidentally fell pregnant. I have two kids previously, 7 and 5 and this is his first. He was very scared at first and went from being excited to terrified. He said he thought we should have an abortion but I said I didn't know if I could and would have to think about it. Fast forward a week and we took some time to settle, and he came back saying he thought we should do it together. And I was thrilled as I really didn't want to do this alone and I also didn't want to have an abortion. 
So everything is fine for about a month. Then suddenly he is scared again.. he is turning 26 and I guess isn't ready to grow up. He has commitment issues do to his first relationship where she cheated on him and left him with all their debt and he was young and it just always played a toll on him. So I didn't see him for two weeks he said he didn't know if he could be a dad, or support us, or wasn't good enough to do this. After the two weeks he messaged me apologizing and saying how sorry he was and it was just fears but he did want this. 
Now fast forward another month, three months pregnant, and I find out he has been messaging another girl. Just flirting texts and there was videos of each other sent of them masturbating... I was heart broken... she didn't know about me and as soon as she did she contacted me. So then he apologized you know the cliche I'll never do it again blah blah, I loved him so much and wanted to be a family I said okay.  Fast forward a week... and he tells me he can't do it. He doesn't love me. He said he only came back a month ago because he thought it was the right thing to do... I had no idea. I really thought we were happy... 
it's been almost four weeks now, and they have been the worst in my life. He is 100% he doesn't love me at all. He has already started dating and is on plenty of fish and tinder. I know of one girl he saw twice and she was 18... it's almost like he is trying his best to do everything to be "young" and not grow up. They didn't sleep together and she isn't seeing him anymore because she found out about me and the baby. 
He is very serious about being in our babies life though. And wants to come to the scans and be involved as much as he can. 
Which is obviously good. After three weeks of arguing we are finally "friends" he told me today that the door is closed for us and he only wants to be friends from now on. 
 But I am so heartbroken.... 
I have two questions, firstly, anyone else going or been through pregnancy alone? How did you do it? I am so scared and isolated. I have a great family and friend support group, but it isn't the same as a partner... and the thought of him with other people 😔 he told me he isn't seeing anyone else right now, but I guess maybe soon he will be... 
and secondly, has anyone been in a situation that the babies father came back? That he was just scared and trying to be free one last time almost? Am I silly for getting my hopes up he will come back? 
I keep thinking maybe at the gender scan in four weeks he will see me and the baby for the first time and come back....