I'm not going to address most of the topics in your post-because honestly, between Dingedheart and Galagirl-I think they covered everything I would say.
But-I will say that there IS a difference between being exclusive in Kink and being exclusive period.
I am poly, my husband is poly, my boyfriend is mono.
BUT-when it comes to D/s, that is EXCLUSIVE. No other Dom's, No other sub's. Period.
So, I do frequently refer to us as exclusive if I'm talking about D/s. Whereas, we are in no way monogamous.
And, when I say Maca and I are exclusive in D/s-that is NEVER intended to imply that I don't have a boyfriend-he is certainly not a secret.
My point here is-
I don't happen to agree with a lot of what is going on in your dynamic, based upon what you have posted.
BUT-in this one small detail, I think you may have taken the information incorrectly. (you also may not have).
It is quite possible and would be reasonable to assume-if he is OUT as polyamorous in general-that he wasn't in anyway trying to deny your EXISTENCE as his lover, by saying he was exclusive in the Kink community.
As to the rest-yikes.
"Love As Thou Wilt"