It sound like things are going wonderfully for you all, and it also sounds like you're handling everything in a very same manner, kudos! In case you haven't seen it, this site and this page in particular are great: www.morethantwo.com/coupledating.html
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.