It's rare that I agree with men like Jerry Springer. However, his words ring true here. Cheating has to do with morality. This gets to the heart of not our sexuality, but how we use it. Cheating on your spouse is immoral.
Anonymous sex is immoral.
Promiscuity, be it gay, straight or bi, is immoral. But do not confuse orientation and morality. It's our conduct, our use of our sexuality, that makes it immoral. But, as glbt folk we are always condemned, and singled out, simply for our orientation. We are called immoral simply for being gay, lesbian, bi or transgendered.