Thank you for the answers.
It's not like I'm setting it up as an ultimate goal, it's just it seems that other kinds of experience turned out to be... not very satisfying.
I thought hard about why and I realized two things:
1) I won't ever be happy as a unicorn or something like that (yes, I went and learned some terms, too
) because being a secondary partner in a structured poly relationship drives me crazy. Been there, done that. It's not so much about attention but that I feel like the gamma of the pack.
Not powerful enough, not enough of a decision-maker.
2) I also feel uncomfortable when my partners form important connections with other people without me participating in them (and sometimes even without me meeting those people). I guess I'm a bit of a control freak. I'm fine with group experiences or with having multiple relationships of my own, but the idea of my partners having an "independent" connection that has absolutely nothing to do with me... not sure I'd be able to be comfortable with that for an extended period of time.
Maybe GroundedSpirit is right about the shiver.
Though the classic mono model also turned out to be uncomfortable and restricting.
So I guess I need to do more thinking.