It isn't necessary to have a primary/secondary hierarchical approach to poly. It sounds like D has a number of casual relationships with people he simply doesn't consider "partners." They may be sexual partners but that's about it. If they are just FWBs (friends with benefits), I can understand both his and Q's stance entirely. What a waste of time and energy to meet all the people he's involved with, especially if they're just folks with whom he has casual liaisons. The important thing to find out, IMHO, is how he practices safer sex. However, there just may not be enough of a basis of relationship with them to warrant introductions and developing camaraderie with other people he's with. But don't assume that he isn't honest with them about having other relationships; he probably is.
I understand it because I am "solo poly" myself. I have no desire for a primary partner and keep my relationships separate. It would just be weird for anyone I date to formally meet and try to have a connection with other guys I date. Right now I am in transition; I have one steady lover-friend, whom I call Lively on this forum, and I am in the process of starting new relationships with about three or four potentials. If I asked any of my potential lovers to meet Lively, everyone's reaction would probably be, "Huh? That's not what I signed up for. We just met. I want a nice, comfy, casual friendship with sex. I don't want to jump through hoops and meet your other lovers for that!" And Lively would think I was off my rocker. In fact, I think he would be very uncomfortable with meeting anyone else I have a relationship with, even though he and I have thoroughly discussed the fact that we are not exclusive, and I know he would be happy and compersive for me if/when something takes off with these other guys.
Originally Posted by UnderMind
. . . from my perspective, there's no chance to ensure there's informed consent for all parties involved, no opportunity for dialogue, his partners have their right to a voice and choice denied to them, no way of ensuring everyone is OK and no opportunities for compersion.
Hmmm. What makes you think that none of the things you mention can exist for any of D's lovers unless they meet all of his other lovers? Both Lively and I would have compersion for each other if we never meet anyone else the other is seeing. Our other partners or potential partners know we are involved even though they will never meet. Why would meeting you and Q magically grant D's lovers a "voice?" They may be perfectly satisfied just knowing that D has other people he is involved with, and not feel any desire to meet them.
So, that's just another perspective that I think may relate to how Q and D feel about it. Perhaps if he had a commitment to a serious primary partner, the parameters would indeed be different. But he doesn't. He doesn't have partners; he may have flings, fuck buddies, casual girlfriends, or FWBs -- but no Partners with a capital P. Your agreement is to meet partners. I don't see it as being broken in this case, since he doesn't have that kind of partner-type relationship with anyone. Think about it this way, if he has a one night stand with someone, are you going to insist on meeting that person the morning after? Also, Q would likely be another one of his casual relationships. Is she ready for that or does she think she will be some kind of primary for him? Will she be able to handle it if she may never be "elevated" above the others in his view? Just something to think about.
Added: You did say there are details you left out of your original post, so it's possible my viewpoint won't hold water if there are other glaring issues or reasons not to trust this guy. But I offer my perspective as just that -- another perspective you may not have considered.