No real first hand experience. I kinda interacted with people that were /are poly, but wasn’t part of their group.

But the thing I noticed about poly groups regarding the kind of stability that would be a success in any objective view, is that there’s usually a core few that comprise the true group, with anyone else being kinda replaceable. It’s usually either a “throuple”, or two pairs, and those core relationships are what really matters when there’s any trouble.

Imo, that makes sense. In a real world sense, nobody loves everyone equally. It might get close, but we as a species just aren’t that controlled in our emotions. They’re shifting and tied to so many different memories that it’s barley possible to have comparable levels of love, much less exactly the same.

And, there’s the issue of numbers and work. If a couple has X amount of work to maintain, a third person doesn’t turn that into X+1, it turns it into X^3, because you have A×B, the first two, then you have A×C, B×C, and, A×B×C. The dynamics of each pair of individuals is the same, but you add the dynamics of the group to that. Add a 4th person, and you get X^4, and so on. So, the larger the group gets, the harder it is to actually maintain every relationship at all, much less equally.

But! I know two poly groups that have been stable for a long time. One since the mid nineties, the other since 2003 (officially, but they got together informally a few years before that). The older group stabilized out at five people back around 98, when a couple that had joined in decided it wasn’t working for them.

The other group is essentially a foursome, though they tend to rotate through twosomes over time. Like, one couple spends a few months more focused on each other, then the other two people either do the same or float a little as individuals without as much group interaction. But they’re all bisexual as well as poly, so there’s that helping out a little; everyone is into everyone romantically and sexually, so there’s less chance of someone feeling left out.

Both groups have kids, btw. Which can get a little tough on the kids in school, but damned if it isn’t a plus at home. Like, those kids never lack for someone to help them, give them affection or discipline, or anything. The oldest boy from the longer lasting group is out on his own now, and doing well for himself.

The only other poly group I know well enough to have picked up details about their arrangements went back a lot further, back into the sixties when they met. Which is a success, if you ask me, but there’s only the one lady left now, and that’s fucking brutal to lose three partners that you love like that. I don’t know if it’s any worse than losing a monogamous partner or not, but holy hell has she been through some pain over the last two decades.

I call them a success though. They went through fourty-plus years together, raised kids, lived life, and stuck together. I didn’t meet any of them until one of the guys had a stroke, back before I got hit with the disability stick and had to quit working. I was a CNA, and when he had the next stroke, they asked if I could come back, so I got to know them a good bit. But they’d lost one of their group between times to cancer.

For myself, I don’t think I could handle that part. I know that if my wife dies before me, it’s going to break me. I can’t imagine going through that two or three (or more) times.

Which is probably not the most pleasant way to end this comment, being a bit less happy than maybe you were wanting. But I figure if one group of people can live poly together long enough for that, then polyamory is nothing to dismiss, and it’s certainly proof that it can be satisfying and good.