sORRY still believe in monogamy.

I discovered that I don't have any sexual jealousy at all. I really don't care what a partner does with who, sexually, as long as they're honest about it, and they're sensible with respect to infection risk.

Where I can get jealous is over the emotional connection. This became very clear when it became obvious that my ex would rather spend time with her 'friend with benefits' than with me. They'd constantly be texting and phoning, acting like teenagers. Then our (mine and her) trips to Amsterdam became their trips to Amsterdam, and so on.

So I think poly would only work for me in the sense of 3 (or more) people, all with an emotional connection with each other (or at least all with one with me.) I could be the hub if it suited the other parties to be spokes, but not the other way around.

If all parties are fully invested in it, I can see where it would be beneficial to all involved- even the children since more loving adults cannot be bad for child.

From a health/phylogloy stand point monogmous is the best. If you are into fantasies fulfillment then a Ménage à trois might be for you.

I think that as a society we need to be more open. Tho I'm not at all a fan of Mormons, nor do I think that their polygamy is fair to women, I don't know how it's the government's business unless Food Stamp fraud is involved or abuse of the women or the kids.
I think it has to be up to the individuals in any relationship & I agree honesty has to be the foundation.

I think individual humans can progress towards polyamory, monogamy, chosen singledom or whatever they like, rather than "we as human beings" aiming en masse for any one of them. Personally, I can't imagine being anything other monogamous (and if my partner can't meet all my needs I'll make compromises, just as I hope my partner will for me, because I believe that's how relationships work), but what other people do is up to them.

In the case of your ex, did he tell you he was going to be polyamorous at the beginning of your relationship, or later on? If it was at the start and you went along with the relationship knowing that to see if you could live with it, fair's fair (but I'm glad you got out of it - or I assume so, since you said "I was seeing" - as you clearly weren't happy). If he announced it later on, I'm even more glad you got out of it - if I'd been in your situation and he'd announced it after letting me believe I was in a monogamous relationship with him, he'd have been straight out the door.

Poly for some, mono for others. People are different. We don't need a uniform mating requirement.