Hi again. Everything you've said in your last three posts does make a lot of sense. I do understand your viewpoint. It sounds like it is working very well for you, the only sticking point being that he has not been honest with her about what he's doing. If he tells her, and all three of you continue as you were, openly and honestly, it sounds like a good arrangement. You are certainly very intelligent and aware and have made your choices and accepted them. I can admire your strength, although I would make different choices (I think). Sometimes you don't know what kind of situation you will find yourself in. At this point in my life, I don't think I would like being in a triangle with that dynamic, but I understand it.
Just wondering if there is anyone else in his life that he has the same kind of "friendship" with, that he has with you. If you discovered there was someone else he was seeing, how do you think you would handle that?