It occurs to me that I may have muddied the waters too much at the start here. I wonder if this all woulda made more sense if I'd included Mono's quote and then just asked "Is it easier to join an existing two person relationship as the 'third', whether the format is triad or vee, if you're naturally comfortable being a 'supporting actor' much of the time in your life generally?"
Like, leave secondary relationship roles out of it, leave submissiveness out of it... hmmmmmm... or am I just grasping at straws? It's so fun to have a pet theory but they so often disintegrate when you expose them to the light of other people's experiences and perspectives! That, of course, is one of the best things about having a community.
Me, 30ish bi female, been doing solo poly for roughly 5 years. Gia, Clay, and Pike, my partners. Davis, ex/friend/"it's complicated." Eric, Gia's husband. Bee, Gia and Eric's toddler.