Okay. Just finished reading all of your posts and enough of the responses to see which way the shit was rolling.
The mumsnet massive heard "no rent" and lost their collective shit, ignored everything else you've said and started making stuff up and chucking derogatory allegations based on supposition, didn't they? I couldn't be arsed to read any more of their invented ignorant crap OP but I'm certain it happened.
If normal patterns hold true, you mostly got the one-eyed, single track minded (property/rent/morgage) dyslexic misogynistic goat response.
So, here's a response from someone who was listening to ALL you said.
He is using you as cash cow and free childcare. He is a liar with special attention to being deceptive over money. He can't even pay full price for his own housing, to the tune of his family covering two thirds of the market rent and you paying half the bills (I suspect it's more than half and is much more than you've actually taken into account), more than your share of the entertainment budget, ALL the food and paying for his child.
If you carry on down this path, he is going to use you up, spit you out and fuck off with at least half the value of the house you've paid the majority in to.
You've got your suspicions of this already, I can tell, but you've just about still got your blinders on because you are in love with the idea of this lovely little family life together that you are imagining. He's not going to provide it my financially responsible friend, at least not in the long term. You've said yourself his mask has started to slip in the last couple of months, as is what usually happens when these future faking fuckers sense you being trapped in his orbit by a new baby. If it's going to happen, it's usually during the first pregnancy. Is that what happened with his ex and is why she's making him cough up for extra clothes for DSD, or thinks she is because she doesn't know you are the one paying, by keeping all the new clothes at her home.
He's no good. He's up to no good.
Run and if you can't run, beware.
Sorry if that's not what you wanted to hear but I'm more interested in your welfare, and that of your baby, than his.