Great question, Dagferi - I don't think I'm even comfortable calling it a triad, most of the time. We have three couples, we have time with the three of us together, but to really call us a triad seems a bit early. I wouldn't feel comfortable doing that until, I don't know, a year or two or four? So, the answer is: can't say.
Right now, maybe it's easier to call it dating - just lots of it. Using the word "triad" is, for me, a way to define the space in which we're doing our dating, not a definition of our relationship status. We're flowing toward what feels right for us, adjusting as things develop. It's pretty fluid, right now. We are three dating couples involving only three people, with an additional "three-person organism" out there, as well.
For what it's worth, I've known a few triads that have lasted a decade or many, some living together as a threesome, others happily not living together, and one a "third" living separately from a well-established couple. I'm going to paraphrase Dan Savage on this one - you rarely see third anniversaries of triads. But mostly, from the ones I know, it's because they don't give a shit about broadcasting what they're doing. They just live.