Hi J - given the sitch, I'd be inclined to try to get some help in so you can work a little (not too much - but just enough to keep your hand in and your name out there). SO just seems so unstable still, and the power dynamics of the R change when you are totally financially dependent on him. I know from experience it's hard to work when you are getting up at night with a baby, so I wouldn't take on too much - but just enough to keep you connected.
Maybe SO will surprise you and be happy about going back to work full time. It doesn't really seem as though he's organized his life all that well these last two years, does it? Perhaps he'll be secretly relieved to be back in that routine.
Is your mom going to be staying with you? Be careful about space and boundaries. My H's stepmom came to stay with us when my oldest was born. Although we were grateful for the help, my h really resented the intrusion on our privacy as a couple and new family.
