But then they're not running into other bi's. Years ago I saw an episode on Jerry Springer involving one guy in his late 20's, his wife and the wife's girlfriend. The situation was that HE encourage his wife to get involved with some woman. Her reaction was "I didn't have any strong objections to it, so I did."
HIS complaint was that she got involved with a LESBIAN. He had figured on threesomes FOR HIM. The OTHER woman's attitude was, "Hey, dude, I'M only interested in your WIFE." He was like, "Hey, this was SUPPOSED TO be for MY enjoyment!"
Sucks, doesn't it ...