Adrian is the son of poly-amorous swingers, so who knows what his reaction will be, though he looks fairly shocked in the last panel to say the least.
He seems like he isn't necessarily looking for that kind of relationship, though obviously it's been dumped in his lap. If the harem turns into a sort of poly/swinger collective, I think it'll make things inherently less interesting, at least for me - that's something that people already do, at least with higher frequency than male dom + x exclusive female subs. And there's a heat to it if mind control has created that sort of "harem" relationship.