Just like to add my thoughts and best wishes to you all through what must be a very hard time. You guys give so much to everyone else it is not at all surprising there has been so much concern for you in return.
There is obviously no magic bullet that will sort the pain. It has just made me remember that one of my biggest fears about poly was always "where will this end up?" I guess maybe that's what Polynerdist is facing now?
Although at present Z's OSO isn't interested, his dream is to have the three of us living together. He sees that as his ultimate. Oddly it doesn't worry me too much. Other things would worry me more and although he has made promises; when you're dealing with intimacy and love you never really know where, or how things could end up.
When I accepted Z's polyamory I also accepted the old adage "When you love something set it free, if it comes back it is yours, if it doesn't it never was" And just as importantly to hold on too tightly we can crush and kill that which we love.
You're the one being held onto and it's a crushing experience. I have learnt , however unpalatable, that when something is really causing me grief the best way through it is to engage with it more fully, more completely, more positively. I know, the last thing you probably want to hear but it works in quite surprising ways.
And here endth the ramble