Is it cheating when (say your a guy here) your married to a bi chick and you have a three some? Yes No
threesome implies consent, which in turn makes it not cheating. cheating is something that's done behind another persons back, without their consent. If it was just two partners and they slept with other people, not in threesomes, that's polyamory - if everyone's consenting.
Totally agree......3somes have consent from all parties, (hopefully), cheating is done behind someones back. mmmmmmmmmm.........3some!
It's obviously not fucking cheating if it's a threesome...which means that you're a part of it 'cause you want to be, which means you know about it...so yeah, it's a retarded question with a simple answer.