Great piece! I've been curious about RA since I heard the term a few years ago, as I consider myself at least a small-a anarchist.
The piece helped me realize that one of the biggest heartbreaks of my life was due to something that is well-described as an anarchistic relationship and the violation of that by the sexual hierarchy;
I basically had a non-sexual, romantic relationship with someone, and intended to live with him for the foreseeable future. He had a sexual, romantic relationship with a third party. This was well and good until he decided to, with that third party, abruptly stop living with me so as to travel the world with this third party, with no firm intention to ever return. He eventually married and now lives (far away) with that third party.
It's been very hard for me to articulate this to people, as the level of intimacy we achieved was far beyond a normal "friendship" (e.g., consisted of hours of time per day talking about our fears/ dreams), but it was also the case that we had no explicit label.
I think this could have been helped, of course, by having an explicit, serious conversation about what kind of rules we wanted for our relationship, and if either of us had known about RA, that probably would have liberated us to realize that some ways that RA folks do things could have been ideal for what we wanted.
So, less than an identical twin is the same person. The criterion above still holds.