I am aware that we can change the case to remove the considerations I raised. My suspicion is that once we do, the intuitions you claim as strongly shared will no longer hold. This because I suspect that our negative reactions are a product of the background social meanings, including empirical assumptions about what a person making those demands is likely to be like and the likely results one way or the other. I think these are good enough reasons to ground a negative reaction to most of those cases, at the level initially described, although on certain extensions–your neurotic person, perfectly harmless but prone to be jealous, unlikely to ever change despite years of therapy, etc.–I also find it obvious that initial negative reactions should fall away. The best thing for such a person to do is to find an unusually introverted partner, one with whom they can build a mutually fulfilling romantic relationship that does not require the things that they are unable to give. Perhaps you disagree! And perhaps I am wrong about how others’ intuitions would change even on such extensions. Regardless, the claim of bad faith engagement seems misplaced, as this strikes me as a pedestrian disagreement over whether a thought experiment really shows what it’s supposed to.

In general: I agree that requiring sexual exclusivity of a partner is a restriction on their freedom, and also that it is therefore at least prima facie bad in an evaluative sense. But this prima facie-ness is incredibly thin. Any preference on how a partner might do or be is that kind of burden, insofar as almost any activity or mode of being could conceivably be enjoyed, and hence any preference on how a partner be or act restricts conceivably valuable exercises. Someone who wants to ‘check in’ with their partner by phone every night restricts their partner’s ability to be away and out of contact, and separation is valuable for some. Perhaps it would be better if everyone were flexible on this matter, rather than taking a stand one way or the other, or perhaps it would really be best of all if they just took whichever stand you think does better in the space of reasons. But that evaluative fact about how it would be nice for people to be, even if it is one, tells us basically nothing deontically about how actually-constituted people should carry on in their relationships. It especially does not tell us that it is morally wrong for a person who wants to check in with their partner–even if they are doing so for rationally shabby reasons, like unwarranted and clingy anxiety issues–to go about finding a compatible other and then build a relationship with them. Deontic claims will depend on all sorts of further facts, and those facts will definitely include reference to whether there is a practical prospect for change. People go to therapy for their whole lives without solving their anxiety issues. Learning to manage them in part by scaffolding one’s life with relationships that don’t exacerbate them ~is~ a form of rational, responsible, and effective agency.

This is not to claim that everything is innate, and no one can ever change. That’s absurd but also obviously not the claim I need. The claim I need is “it depends, and and at least some prospects for change are unrealistic.” That, by contrast, seems pretty hard to dispute.

Consider a case that strikes me as completely parallel, namely, that of a world free of parental attachment. Perhaps it really would be desirable if we all raised children collectively, not just in the sense of involving multiple significant figures like aunts and uncles, but in the sense of utopian communist style fully shared parenting without even nominally distinguished responsibility. I certainly don’t believe that the notion of parental love is intrinsically or inherently one or two-to-many, instead of many-to-many, and the prospects for some in-principle rational justification of traditional parenting relationships correspondingly strikes me as incredibly dim. Indeed, more strongly, it strikes as plausible that the partiality involved in the traditional parenting stance is rooted in actively bad and indefensible underlying values and dispositions. But it nonetheless really does seem like, given our cultural background, people have significant concrete psychological predispositions toward exclusive parenting (n.b. this is not the claim that there are no conceivable cultures where this is otherwise, and my impression is that anthropology teaches us that there are). But given that many people in our culture do feel this way, and the prospect of them coming to feel any way otherwise are weak, it would be strange to say the equivalent of “[t]here is thus a call, not yet adequately responded to by philosophers, for greater clarity in the reasons why it might be reasonable for a couple to adopt a policy of [parental] exclusivity.” It’s clearly reasonable for a couple to adopt a policy of parental exclusivity. They be skeptical that any other policy will be compatible with the future flourishing of them and their child, and even if not absolutely convinced of this have an obvious prerogative to play it safe. Furthermore, they may–should, if they do–hold that attitude independently of whether they think parental exclusivity is intrinsic to parenting as such. What happens in conceptually possible but speculative utopian fiction, e.g., or what has managed to be well-practiced by a far-flung and vastly materially different culture–those are not the right questions for a reasonable couple to focus on when deciding about what to do with their actual child, even if they are interesting in their own right for other purposes.