I'm not sure if you'll be interested in my answer, since the triad I'm in is very atypical (see my signature). But anyway, it's very easy for us. We all met on the same forum. A and I met first and started a romantic friendship. Then L appeared, all three of us talked on the forum a lot, and I started to talk to L in private. Very naturally, we all came to think the three of us could make a wonderful triad. It was pretty much like two friends both befriending a third person, and our triad is essentially based on deep friendship indeed. The strong friendship component enabled us to connect as three equal individuals with none of the typical unicorn hunting drama.
Seeing that I'm married to someone not in our triad, exclusivity is clearly out of the question for us. Even if I wasn't married, none of us wants an exclusive triad anyway, because (at least for me) that's no better than monogamy between two people.
Heteroromantic asexual female, sex-positive, childfree, relationship anarchist.
Married to G, and in a partially non-romantic, completely non-sexual and long-distance triad with A and L.
Last edited by Eponine; 11-15-2013 at 10:47 AM.