It appears that you are looking at this as if it is you and him....and everyone else is outside being invited in. It also appears that, from his perspective, he began dating you, and met her at about the same time, and feels more or less equally about the two of you.
I think you are more in "couple" mode; whereas he is still in "dating" mode, even if the two of you have announced as a "couple" in the kink community, you are still a new couple, and he is likely still figuring out what that means to him.
It might help if you think of it as how you, he, and she can work together. Instead of how you and he can work together to include her, or "others."
Also, I understand you feel strongly for him, but after a couple of weeks, he may get scared off if you get too serious too quickly....especially as it looks like, as several have mentioned, you expect to be able to control his relationships.....even as you have other, independent relationships of your own! Expectations of exclusivity, or even "being a couple," need to be built up to....not taken for granted. If that is what you, in fact, want (You and A to be the primary couple, and all others secondary).
Last edited by PolyinPractice; 11-06-2013 at 03:36 PM.