Hey, just wanted to say that, as someone in a poly relationship with a new parent, it's nice to see someone else who seems to be successfully managing it so far (I know it's early days, but everything you've written sounds very reasonable and workable to me). Some poly folks seem to think that pregnancy and then the first couple of years of infancy are just not a good time for multiple relationships, because there's too much other stuff going on. It HAS been hard at times (what relationship isn't?), but I'd like to think that, because I can help out with babysitting or in a crisis, my presence in the lives of the new parents has actually made it easier for them overall rather than harder.
Anyways, best of luck.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.