Thanks for your words, naturalblue. I feel this week, I am very close to that breaking point. Last night, when she was practically threatening to ditch our date night to be with her guy, I was running various break-up scenarios through my head, planning to make the break. But she relented and went on the date night with me, and even though it was full of a lot of her NRE-induced B/S, she did go home with me and sleep in our bed. Today she was actually kind to me the few times we communicated, but she is headed out tonight to be with her guy and won't be back until tomorrow night. She knows about my 24-hour rule, and we'll see if she tests me on that again.
I've decided what I'm going to do about that. If she crosses 24 hours and is not home, I'm going to call her. If she comes up with some lame excuse, or downright refuses to come home, or tries to invalidate my feelings again, I'm going to go ahead and call off the polyamory, and call her guy and talk to him about that (because honestly I don't trust her to relay my frustration to her guy adequately). Then we'll finally get some resolution one way or another.