I've been in like, 3 or 4 of them so far. I can really see the value in a poly relationship but I find it, that it's incredibly challenging to maintain much less establish one. All of the ones I've been in, was where the individual wanting or orchestrating the poly relationship, was just a flat out cheater who wanted more than they can handle. My limit is no more than 2 other partners. The people I kept finding myself with, practically wanted like several partners too many and it just complicated things.
I'm open to being in a good one but I really don't know nor would I know anything or anyone that'd want a good stable poly relationship.