Thank you for expressing the difference between “open” and “poly.”
To me, from reading and observation, open is just sex. Poly suggests feelings could be involved, temporary or long lasting, with and without the “primary” (or rather originating?) couple both being involved.
I know people in polycules, where each is considered married to all.
I was originally put off by the hierarchical nature of so many triads I saw growing up.
Here is the rub, open can wind up with a pregnant second partner, a divorce and the originating couple blown apart, ending the love between them, functionally.
Add the number of people who will lie and say their marriage/long term partnership is “open” or “poly” when the other is unaware and the slimeball making the pitch is simply cheating.
Earlier, I responded and used the phrase relationship management, and said it’s not for me.
The headaches of multiple partners outweighs any potential benefit, to me.