Thanks for that RP, and no, it's definitely not damaging my self-esteem. This wasn't about me, but about her inability to be honest. And yeah, I did go into her room that time she was cringing and I asked her to talk about it, I asked her to tell me what was going on and what she wanted. She shrank away at that and shut down. But you're right, RP. In hindsight, I should have pulled back clearly from both of them and laid down my terms then. As it happens, I didn't until after she broke it off. (in this case, I honestly think it wouldn't have made a difference in the outcome, but yeah..for myself, it meant that I was compromising too much and not holding to my normal standard of communication and honesty)
Even after she told me she wanted to return to monogamy, I asked her again what she wanted as I did not want to be in a place where I was not wanted. That's where all the fuzzy non-committal friend stuff was coming in. I made a decision (a decision, as you point out, that should have been made sooner) that I wasn't going to settle for anything less than honesty...which in effect destroyed the friendship, but for all the right reasons.
I'm just taking the lessons learned. I know that a closed triad is not for me..not just because of this bad experience but because of other stuff that just didn't suit me throughout the relationship. I know that I could have avoided a lot of unnecessary pain if I had just pressed for honesty sooner and not just allowed her continued denial of feelings. I know that I am worth far more than the way she treated me and have just that much more strength to stand behind my worth now from that experience. It was good practice for standing up for myself and for not taking on the problems that weren't mine. I'm going to keep reminding myself of what you say, RP.