I think we're a bit similar to you guys. My partner Z is poly and I have been mono but have decided that in a long term relationship with a poly, it is going to be much more fun and easier to give poly a go myself.
He was getting very discouraged like you. Has a long distant OSO but wants a local one. Like you heaps of women, none of who want to share. All looking for one on one life partners.
Anyway, suddenly last week a poly popped up on his radar. And even better, a bi-sexual one, so yay for me too. We've text and chatted on line and all seems really good. Meeting up for lunch in a few hours.
So there you go, patience is a virtue, good things come to those who wait, hang in there.