Proust said the best marriages have infidelity hovering over them like a threat. But with polyamory, it's not a threat, it's a promise.
No, with polyamory, it's not about infidelity. It's honest and open non-monogamy. Huge difference. Infidelity is about sneaking around, lying, violating agreed-upon boundaries, disloyalty, and untrustworthiness.
I want him so much, I assume I can't have him, that something--anything--will get in the way.
But you do have him. Just not in the conventional sense.
She's monogamous and I have a really hard time believing she's all that happy with the situation . . . Plus she's the face of my guilt . . . I'm not sure how open he is with her about us . . . I can't put my finger on the line between permitted cheating and more than one true love . . . The solution should be to talk things out with her, but I know her interest in that is low.
You have nothing to feel guilty about if everything is above board. It sounds like she knows about you, but perhaps not all the details (which is fine). Simply put, you are involved with a man who loves more than one woman. Again, it seems you don't quite see polyamory as much more than having permission to cheat, but I don't think it should feel that way. Perhaps this sense you have is an indication that some conversation with your guy is needed first, so you can get clear on how open and honest he is with her. Or, it could just be your insecurities and unsureness about the whole thing, which, in that case, could also ease up if you talk about it, but you might need to be careful not to make it a messy conversation.
The point I was getting at, perhaps gracelessly, was that I'm--in traditional paradigm talk--the Other Woman. The Other Woman role includes insecurities about how legitimate you are, how he really feels. When the day is done, we seem to cause each other incalculable depths of rare and rolling joy. When the day is done he goes home to her.
You are not the other woman; you are one woman involved with a man who has two in his life. Calling yourself the other woman really sounds degrading to me. Everything you express seems to show that you have not really resolved for yourself what the situation is, what polyamory is, and how it is different from cheating, affairs, infidelity. I think you need to let go of the wistful hoping that the situation was different. This is usually where people get tangled up in conflict -- we think things should be different from what they are.
In many cases, of course, we find ourselves in situations that need to change. However, the way to have what you want is to start by looking at where you are, without comparing it to what others have or what you think you should have. Just take stock of what you've got with this relationship, without giving credence to that dialogue in your head tell you it's wrong in some way. Then ask yourself if it's okay, or do you want more? Or something else? If so, then, sit with that for awhile, you may not need to act on it right away. But oftentimes, what we need comes from inside us, not outside.
To me, it sounds like you really have a good thing with perhaps the need for a little more communication to get clarity on some issues.