I suspect people who reject this silly notion tend to still get slapped in the face with it. As in the article, when you are forging another relationship with s

I suspect people who reject this silly notion tend to still get slapped in the face with it. As in the article, when you are forging another relationship with someone else, their attitude and opinions about your existing relationship are going to matter. When something goes wrong, they can't just ignore your other relationships, they'll have to form some kind of opinion as to how they factor in. It is straightforward to feel threatened by them. If you have 3 people with strong relationships (between at least 2 of the pairs), you have a classic triangle. If there is a two-person activity and A chooses to do it with B, and C wanted to do it with A, then there is some level of conflict. I'm not saying it's an impossible situation by any means. The triangle problem only comes up when the interests of the pairwise relationships overlap. (If C hates watching Gerbils On Fire, then C is unlikely to be bothered by A and B binging season 3.) But they'll often overlap at least somewhat. (C was hoping to watch Knitting With The Rats that same evening.) And it's not like pairwise relationships lack similar problems, so you don't need to compare to perfect. It's just that "giving up on this silly notion" isn't enough to erase the problems. A may not raise his relationship with B over that with C, but there will still be situations where both relationships can't occupy the same space or time.