OP. If you wait for a man like this to spontaneously see things differently and mend his ways, you'll be disappointed.
If you try to get on his case and persuade him to change, you'll be disappointed.
There is no incentive for him to alter his behaviour. He will clearly not do it out of the kindness of his heart.
If he won't work, he shouldn't eat. Or at least you shouldn't cook for him. You will make yourself unpopular, but how bad will that really be? Will he stop acting in a loving way towards you? Sounds like he's already stopped. A loving response would be to see you're troubled and want to do something about it.
Perhaps he's burnt out and perhaps he's depressed, or perhaps he's just plain old selfish. It doesn't really matter WHY, it just matters BECAUSE.
If you can stomach it, I would harden yourself and refuse to see the dirt for a short while. Forget dropping hints or talking out loud in the hope that he will 'remember' - just see what happens. If he does more, great, continue that plan. But I will warn you, his threshold will be higher than yours. You're wanting your nest to be just right for your new addition to the family, not some pig stye. I'm not saying live like that forever, but just for a while. Try to make him blink first.
If that makes no difference then I would only cook and clean stuff for you and your toddler. I would begin to act like a single parent, because you are one already, and you may as well get that mindset. Your H will not like it and so on will have to harden yourself to follow through. Something drastic has to happen. If he doesn't initiate it then as a last attempt, you could suggest couple counselling.
My Mum always said, you have a choice. Be prepared to leave, or put up and shut up. There is no third option, much as you might like there to be. There is no magical knowledge or trick that any man or woman can offer you, to give you the partner you want and deserve.
All of this is of course just my opinion. I wish you all the best. Pregnancy and parenthood is hard enough without this added to it.