Our closed FMF triad was a spectacular failure for the following reasons:
1) jealousy, on pretty much everyones part at one time or another
3) dishonesty, claiming to be at work or somewhere while with the other person, because M was afraid one of us might go out on a date or something if we knew he was busy with the other.
4) M complaining to one F partner about the other, sharing a lot of intimate details or other personal information without permission (drove us both nuts, not just me)
5) playing one partner against the other ("well if you won't, she will, I guess you really don't care about me as much as she does....")
6) Double standard. M was extremely jealous and I got tired of being accused of cheating when I wasn't, while he had this 2nd relationship.
7) lack of communication. I never knew if I was supposed to be there or if he was really hoping to see her that night.
8) we really didnt like each other all that much (the two Fs) or have much in common.