You didn't go wrong, they knew your boundries, and the fact that she initiated a BJ, was her perogative, if they knew that your wife wouldn't then that was thier issue not yours.
My advice to you maybe to find a bi female to play with, if exploring your wifes bi side is the main event. Or another couple with the same intent as you, I am sure there are couples out there with the same intent.
My feelings are this lifestyle is for the benefit of all not just one, If people can't accept your boundries are hard limits and not a thing that weill change at their will, that is their prob. Getting into a relationship to change people never works and only causes heart break.
I hope you find a couple who will accept you for what you are not what they want you to turn in to. There is no standard for any lifestyle.