I tend to agree with RP ....somewhat.
Is it possible ? Maybe. But I feel setting it up as some 'goal' and not feeling satisfied otherwise is going to lead to disappointment and disillusionment.
Because the 'dream' tends to ignore human nature.
As we've spoken about frequently, all people form connections of various depths and in various fashions. There is never this idealized 'equality' any more than leaves on the same tree are all equal.
And I always get a shiver when I hear such talk because to me it harks back somewhat to the 'same old model' - a slightly expanded form of monogamy. Only with one additional person. In such a configuration I see the same potential for problems and conflict as I'd see in a classic 2 person monogamous relationship, but maybe with one important difference.
These people have looked at 'expanded' loving & relationships, chosen it, and I have a feeling that in most cases trying to close that down is going to be difficult.
Pandora's box has already been opened. Monogamy was found lacking (something) in order to choose this in the first place and once discovered that's not likely to change.
Good luck !