So person C enters the relationship and they form a polyamorous-trio, but instead of it being a true trio, it’s more like A & B still have their relationship (now burdened) and A & C have a relationship, but B & C don’t engage much. This is the exact scenario I have witnessed in the only 2 households I’ve ever known doing it.
That is in fact common, but would also not result in “moving in” or “forming a polyamorous trio”. That’s exactly not the point, it’s just one person having two relationships and - hopefully - each of the partners is fine with not having 100% of their partner. Which many people actively enjoy mind you, not spending all the time sitting on top of one another.
In fact I would say that from all the poly couples I’ve know over the years, very few are trouples and want to move in together.
That is in fact common, but would also not result in “moving in” or “forming a polyamorous trio”. That’s exactly not the point, it’s just one person having two relationships and - hopefully - each of the partners is fine with not having 100% of their partner. Which many people actively enjoy mind you, not spending all the time sitting on top of one another.
In fact I would say that from all the poly couples I’ve know over the years, very few are trouples and want to move in together.