"So obviously open relationships are quite private." <-- My parents know about all my partners, as do all of my friends, and a few of my co-workers. Same for them -- their parents friends, and some associates know. I'm in love multiple times over and that's ok... it's amazing, actually. I'm less private than some poly people, but just as or even less private than some others.
I don't say any of this stuff to say "you're in the wrong place, get out of here, we won't help you" at all. I hope that you will find help and support here. I point this stuff out just to make sure that you're aware that you seem to be coming from a very different place than most of the people here may be coming from. Perhaps the responses you get will make more sense with that context.
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.