Her actions seem cowgirl-ish.
I am curious - is HE moving into her room or into his own? Why did he say yes if you weren't asked? Did he talk to you about it before he accepted his offer? If not, why not? Can you move into his room with him if you wanted?
I think all the above and everything you wrote about in your post should be addressed in a conversation with all three of you present. You can emphasize that you are not insisting to move into her place (well, you know you can't really, anyway), but that you want to maintain your equality in your relationship to both of them and want to experience cohabiting in a poly house. Then I would point-blank ask her what her motive is in not including you. Ask her that when everyone is present, and see what she says. It sounds so much like she wants him to herself. And then ask why he didn't consider your feelings before accepting. I mean, I'd be like, "What the fuck is going on here, people?" if I was so left out of the loop in a situation like this where you are all equal. That's what I'd want to know.
Edit: Maybe it's nothing to do with the dynamics of the relationship and more to do with financial or more practical stuff... Can you afford it? Are you responsible and neat? Things like that, maybe.
Last edited by nycindie; 03-17-2011 at 11:35 PM.