Can you take your toddler and go and stay at your parents for a bit. Tell him you need to think about whether you can carry on in a relationship where your needs are so minimised and he is gaslighting you into thinking you're a nag.
Or get him to go and stay with his mother if that isn't possible.
You need some time apart to think about how you go forward before no.2 is born.
If you go to your parents, if/when you go back, tell him the condition for you returning is that the house is spotless and spell out what that means
- everything put away
- all surfaces gleaming
- new loo rolls
- empty bins
- no washing anywhere
- etc
If you are feeling kind and as though it will be understood, I would also say
You are welcome to get a laundry service for your clothes. I will not be touching them. That means you have to bag them up, itemise them, take them to the service, collect them and put them away. I will not get involved.
Same with any other services.
The other suggestion I have is to collect all his stuff as he leaves it around, clothes, rubbish, empty pots and put it all in a bin bag on his side of the bed every day. He leaves a spill and you can't bear it - wipe it with kitchen roll and that goes in there too. His phone charger, his expensive ties, his shoes left by the door, all in there with the half empty crisp wrapper and the half drunk coffee. Just make sure there are no holes in the bin bag.
Honestly, change won't happen without a massive shock to his system. And once you've done it, you have to be brutal. You will never be able to help him out, just once, because it will become your responsibility again.
It is depressing and frustrating that you even have to have these conversations. I am not saying leave, but you do need to say how much easier it was when he wasn't there and how much you enjoyed your house when he didn't leave you an endless trail of stuff to tidy up.
Good luck OP, I really feel for you. My OH isn't great at a lot of things, but he does pull his weight around the house. It would be a deal breaker for me if he didn't.