I know of one extremelly successful triad locally. I'm dating one of the male members
and am friends with the other male and female and their kids, lol.
Right now I'm living with primary, dating Possibility (part of the triad), my primary is feeling out the vibes with another female and has an ongoing fwb arrangement with someone else.
We are all very happy with this arrangement.
I'm not totally sure about primary's other female and know where I stand with fwb but the main people in this alphabet soup are quite happy with the arrangement we currently have.