You feel "like I’ve sacrificed my body, my mind and my lifestyle for him yet he believes his life should be unaffected during this time (he stated this)", because it is true.
The way I see it, your partner must change radically and accept that, from now on, life will be about protecting and providing for his child (and that includes, in the beginning, for you too, because there's no such thing as a newborn or baby: there's the mother/baby dyad). If he can't do this, then he's not man enough and you'll have to do this without him: this doesn't necessary mean that you leave him, it means you figure out what can he bring to the table and the rest you look for in other places. I am all for using (yes, without euphemisms here) these kind of "men" for the benefit of your children. And the first months of a child (up to a year), as you well know, are hard work.
Of course all what I'm saying comes with a caveat: if there's alcoholism involved, I really believe you are better off separated. As they say, once the baby arrives, it will always be worse.
I really feel for you: you should not have to be experiencing all this turmoil at this special moment. You'll have to grief. But, for the sake of your children, you now must put on your strategist hat.
Sending you love and strength 🙏💐