I've never done anything like this myself. Isn't it complicated both emotionally and logistically? Even if I were at the "center" of two men, it seems like a tremendous amount of work to please them.
The whole idea of threesome (least IME) is that the woman at the center is the one being 'pleased', otherwise it is a slut servicing two dominants *lol*.
IME the emotional is the bigger one, if it is a MFF and the female partner of the M feels like he is concentrating on the other woman too much it can cause jealousy, and likewise with a MM f the husband/partner can get jealous if the wife seems to be getting off more on the other guy (and I know of several MFF's that caused a rift when the wife/partner seemed to really get off on the other gal, know of a couple where the wife ended up leaving hubby for the other woman..that said, I suspect those were setups, where the wife already had been with the other gal and used the threesome as cover for getting out..why she needed that, I don't know.....)
