Reading your post, first thing that came to my mind was - really, porn is the main issue here?
(and, as an aside - why is it OK for men to be with younger women, and why is 'weird' when it's the other way around)
Your baby is already here, so it's pointless to mention that having a baby with someone one barely knows is not a great idea.
Or, even more 😳, getting pregnant as a way of dealing with depression, again with the same near stranger that didn't seem a good father figure the first time around.
Your baby is the only person who is important and innocent in all this.
I hope, for the baby sake - you'll find strength to sort yourself out - deal with your issues and insecurities. Figure out what it means to be the best mother to him.
As to your boyfriend (or whoever he is, given your setup) - it's hard to say much from your post.
It's doubtful that he was looking to become a father at this point of his life. And not clear if his presence in baby's life is adding much.
But he is the father, so that boat has sailed.
Maybe, he'll grow up one day and man up to that role. Although, I am not sure it's likely.
Hope, for the baby sake, something changes and he gets to grow up feeling safe and secure.