It sounds to me like it might be time to renegotiate some boundaries based on what you've said. Maybe this should back way up and not be as serious. 7 months is NRE time, not life changing, move in, there are now two wives time. I think you might of sold her a bill of goods on that one. To me its way to fast to decide such things and not appropriate pacing of a poly dynamic. Your reaction to her blog and your claim to your husband now, is why. It becomes threatening, and emotionally overwhelming when the NRE ends and everyone finds themselves in a situation where promises were made in haste and in the glow of good times. To me its better to just enjoy NRE and wait for the rest. Wait to come down from the drunk feeling of a new relationship before talking about serious stuff.
If I were you I would say it like it seems to be and that is that this has changed to a vee, or at best an emotional triad. It doesn't seem you and her are partners. I would request and end to all moving in discussions, have him go visit her for a change so he can see how she lives (or both of you go. After all, she is suppose to move in, wouldn't you want to get to know her life more?) and back right up and do some of the hard work for a bit (like her getting her divorce and being on her own for a bit, you working on feeling a sense of your place in your marriage) before continuing further discussions on a future together.
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