He comes in, showers here, eats food here, brings his kids here to stay and gives me nothing. Hes not contributed anything towards buying baby stuff.
Mate, he was showing you exactly what he's like before you fell pregnant. He's a user.
I've seen a lot of women on here say this about their divorced/separated partners ... Their relationship broken down (usually sue to them, though they'd be we be honest about it) a d they just move into another woman to provide domestic "duties" for them and their kids when they have them. Why would they cook for and entertain their own kids when they can find a woman to do it, why getting sex too.
He's a user, it sounds like it was never a good, fair relationship .. it's easy not to see that. His reaction now you've fallen pregnant totally reinforces that he's not a decent, good guy.
He just wanted a cushy number and he's raging he's been "caught" with a child with you. It sounds like he wanted a termination and he doesn't want anything to do with it.
I'd stop doing anything for him or sleeping with him, any decent man would e stepped up, paid for stuff, and made arrangements to combine home etc. He's not doing any of that and will leave you with a fifth child to look after pretty much on your own.
I'd be interested to know the true story as to why his relationship broke down with his kids mother.