Thank you both...
The relationship had its high points, and there are moments I'll eventually be able to remember without pain. For now, it's all a blur of hurt.
I never wanted to share him. We met her, it was a unique set of circumstances. We all fell for each other (or at least we thought so at the time). It's not something likely to "just happen" ever again, mainly because I'd never put myself in that situation again.
It's not that I am anti-poly. I am sure it works very well for some.
It's just, what he and I have is so good on its own... and I don't need to open myself up to that kind of hurt ever again.