Forgot about this forum. We've gone from trio to duo.
If you're interested, the nutshell version is that she decided to give him an ultimatum instead of being open, honest and communicative in order to keep this relationship alive. He decided he spent 6 years trying to get her to grow up and he had had enough. He and I have moved on together, and she has made it hell for him because she didn't get the answer she wanted. Sorry, but when your life goals, behaviors and ability to communicate don't match up you're not likely to win that battle. Nobody truly "won" in this situation, anyway. We were both, and still are, deeply heartbroken. But, we also know we can look toward a solid future together without the myriad of bullshit that she brought to the table.
In short, we have gotten here in a roundabout manner, but we are where we are supposed to be. Together. I don't discount poly, but would probably not go forth into another situation on purpose. I fell into it the first time though, so one may never know.