Welcome to our forum.
I would say "emotional triad" would be a good word for the kind of relationship configuration you have. The three of you seem to be very close, and it sounds like your poly relationship was meant to be.
You will find a lot of support and wisdom on this site. Explore the various threads, and post any thoughts or questions you may have. The Golden Nuggets board
and Life stories and blogs board
may prove especially interesting to you.
I hope everything goes well for you guys; don't get discouraged if you hit a rough patch here or there. Sometimes relationships are just like that in the beginning, and poly relationships are extra complex.
Glad to have you aboard.