Luz! Hey! :)
Well, maybe you can share about your own process and experience of going from polyamorous to monogamous with openness to sharing partners. I would be very curious to hear more, and I'm sure others would too. I don't have any personal experience with sharing partners, or even witnessing up close this kind of poly-shape, so you probably have thought about it more, and maybe seen more than I have.
Thinking about it does recall a story from that documentary about Tamera that I found inspiring... A man-woman pair, deeply in love, wanted to have kids. Then, she also fell in love with another man. They opened their relationship to him, which deepened, and this man also wanted to have children. So they did. They all have a son together - and the son has two fathers and a mother. In the video, the son appeared to be about 5, and they seemed a very happy family. It doesn't seem that the fathers are romantic with each other, but they obviously love each other deeply as family and they share the mother as romantic partner and mother.