Gosh, that doesn't sound like you're on the same page with this, in a big way. You haven't said where you are in the pregnanacy (though the peeing all the time was all the way through as I recall) - but his attitude seems all wrong here. I would be furious in your position, pregnant or not.
The two of you need to sort two things here (at least!) by the looks of it:
First, the fact that this is firstly your (you, him, babe & to an extent dscs) family home, and only secondly his 'project'. This is something I have lived with a little bit for 20 years, but my DH does listen when I get upset and things get fixed. If he hadn't, there would have been HUGE trouble.
Second, the fact that you, him and the dscs need to get on. I have no direct experience of this, but you have to have agreed rules and ways of dealing with them or everyone will be unhappy.
Have you tried to explain these two points to him? I find it hard to have these kind of conversations with DH as I get upset and he clams up - but once we've got through them, things have improved no end. Don't let it fester.
And congratulations on the pregnancy, too 