So, is it fair to say that he would be in a relationship with you if you were his age and knew you wanted kids soon? Because otherwise, if you both love each other and are living together, I'm not sure why the heck you would avoid the word "dating".
Two polyamorous people dating is different than if they were both single because they've made some kind of commitment to the idea of being in a relationship, which generally means, if nothing else, that you don't just cast it aside when something else comes along.
Did you know, when you moved, that he didn't want to "date"?
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.