Thanks for bumping this thread! It is really interesting. Hopefully this thread isn't dead, and we can continue the discussion?
I think preserving the primary relationship is definitely very important, but I don't see vetos as a constructive way to preserve them. Listening to a partner's concerns and discussing them definitely seems constructive. But a veto wouldn't address the concerns for me and would make me feel less secure about the relationship.
I think this is a very logical way of looking at it, but I wanted to add that "veto" is not always something that exists because one partner gave it to the other. If my husband was unhappy because of someone I was dating, and I believed that ending the relationship would make him happier, I would end it. I haven't given him veto power, but he has it all the same. However, I wouldn't end it with my bf just because my husband was unhappy, because after a year together, I am too invested in that relationship. So his "veto" on that one has expired.
I can see why people would not want to date someone whose partner has a veto, because having a big hammer of NO! permanantly threatening your relationship would be awful. But I can just as easily imagine an awful situation where the partner can't veto each other because they just don't care enough about the other's feelings. Neither of those situations sounds optimal to me, so I don't think the presence or lack of the veto is that important to me. The important issue is why there is a veto or lack of it, and (of course) what are the people like?
I'd rather date someone who has a happy, stable, confidently open primary relationship with veto power, than an awkward, drama-prone one without it.
But going back to the original discussion - prescriptive vs descriptive - I'd like to add a third option as a middle way:
predictive. I am open to the idea that a relationship can develop however it wants, but at the same time, some things are just more likely than others because of what I want, how I live and my current relationships. Dating in that purely "descriptive" way is a little too hands off for me. In some ways, it would seem unfair of me to tell a prospective partner that the relationship was free to go anywhere at all, because that might lead them to think certain outcomes are more likely than they actually are. So although I do not prescribe how new relationships are allowed to develop, I do let people know how they are
likely to develop. And no, I don't always get my predictions right!
I find it sad because I think it speaks to a fundamental problem in the primary relationship--and I have to wonder why'd they'd even consider adding other people to their lives when their primary relationship isn't very strong. Look, folks, if your existing relationships aren't good--and that means functional and strong on every level--then adding more relationships is not a wise thing to do!
I've seen this attitude a lot in the poly community, and wanted to speak up for the "prescribers", as I used to be one. If you took this attitude to its logical conclusion (any desire to limit further relationships shows instability in the primary relationship) then it would mean monogamy is fundamentally disordered. Having boundaries in place in a relationship doesn't mean that the relationship "isn't very strong", or only poly people would have strong relationships.
Swingers generally say that romantic love outside of their relationship would be a betrayal, whereas of course, polyamorists generally do not. It stands to reasons that there would be a whole spectrum of relationships that are in between. And I don't think any relationship that appears anywhere on that spectrum is necessarily stronger or weaker than any other.