I agree.. if you can get to that stage. "if they keep on dating" is the crux. Many folks (at least in my outer circle) dont ever stop. Either always searching for more NRE, or .. something.Unstable in the sense of how most people see polyamory, following only their ego, or if they keep on dating.
I found that a balanced network of love relationships is actually very stable in itself if everyone does their inner work and supports everyone else within that network. Like a interconnected mycelia network.
Its rare to find folks who are at peace with what they have
Thats been my hardest reconciliation to be honest. And a big part of my jealousy. Collectors...