I used to be very deep into the poly community - more than one poly community, actually.

I have known exactly two couples were able to live a "successful polyamorous" life. One was an empty nest husband-wife combination who were already married for 25 years, and the other was a younger couple who both had incredible personal maturity.

I've tried it multiple times, but every "poly" relationship I've ever entered has either 1) become monogamous, 2) been shallow, 3) been short-lived, or 4) all of the above.

I'm still open to it, and I've actually never felt jealousy from it. But I almost never see it work out for anyone's highest interest.