Congrats Jo, Dez is 6 weeks old, and it's already getting a little easier.
Sleep is for sure tough, I recommend start with establishing days/nights right off the bat. Start a night time routine, feed, bathe, snuggle, repeat. Close all your blinds at night, whisper, and keep volumes low. Day time do the opposite, play music while they sleep and let them know it's day time. Our dude figured it out after a couple weeks.
Also, the kid is not here yet, I know you 2 are probably trying to save some cash, but go out, get dinner, see movies, and just hang. It's the last time it'll be just the 2 of you.
There's so many things people don't talk about in terms of just how hard it is, and post partem stuff for the mom. Everyone tells you it gets better, but it doesn't really help when your in the thick of it. It helps to talk with other parents who've been there recently or are there now, and we couldn't of done it without our birthing support. We went the midwives / doula route and it was the best decision we made.
Try to be OVERLY supportive of your wife. You both will be going through a huge learning curve, but yours is nothing compared to hers. Just knowing you have her back will bring her great comfort.
Good luck with everything Jo, it truly is the best, most beautiful, most terrifying thing a person can do.