For me like I said in my post, it's not a concern that "bi person is more likely to cheat, and it's worse when it's with another gender."  It's that for a bi person who might flat out say something like "I am more attracted to women emotionally/sexually", I feel like if we date there's an element of false pretense or wasting our time.  I would not want to be involved with someone whose involvement with me was only giving them a portion of what I was getting.
		
		
	 
That's one of the best things I've read on this topic.  OTOH....
I was at a conference on families once hosted by a Foursquare Gospel church, and one of the speakers began by asking for a show of hands from those who grew up in a family with no problems.  Only a few hands went up out of hundreds in attendance.  He waited a bit, then said, "Thank you.  Now, my topic today is self-delusion...."  He got a big laugh, but he'd made his point, which is that none of us grow up in families with no issues, and none of us grow up without issues -- and he went on to make the point that there are no balanced relationships, only relationships where people strive to keep it on course.
Relating that to here, there's really no such thing as a relationship where each person is getting and giving in a balanced way.  All of us are flawed, unable to give in some ways, unable to receive in some ways.  For most people those are small, even minuscule, but for others they aren't, so inevitably any relationships is going to be one where one or both is "only giving them a portion of what I was getting".  The only question is whether the imbalance is sufficient to be disabling.
	
		
	
	
		
		
			I think the main problem is that the "bisexuality" label is a huge umbrella that encompasses everything that ranges from "I'm 99% into men, and 1% into women" to "I'm 99% into women, and 1% into men".  The people who truthfully lie on either extreme and those that are romantically into one gender versus feel lust for another gender will all be more likely to cheat and break some hearts along the way.  I think the sheer nature of bisexuality including such a variety of people causes confusion and skews the statistics to cheating with the opposite sex (not that this should be any worse than a completely straight or gay guy cheating on someone with the same sex, but hey, who am I to say how one should feel).  Then you tack on all those people who like to hide under the "bi" label while they "explore" their sexuality, and what you get in the end is complete fuckery.
		
		
	 
Any term used too broadly is, I think, going to end up with negative connotations, because it will encompass things someone, indeed many someones, can't tolerate (or at least don't like).
One thing that irritates me immensely is the "hiding under the 'bi' label" accusation, especially when it has to do with exploring one's sexuality.  There's a black/white theme there that assumes everyone knows clearly what his or her sexuality is, and also assumes that a person's sexuality can be plotted on a chart with a point that remains in place.  Both of those are not just false, but dangerously false!  The more we learn about sexuality, the more we see how fluid it is -- and since sexuality is fluid, the admirable standard in xb's post above is essentially impossible to achieve:  what is fulfilling in a relationship one month, or season, or whatever, may not be fulfilling in the next month or season.
The accusation irritates me especially because I've known lots of people who only take the "bi" label while exploring their sexuality because everyone else demands they have a label.  Human beings are great pigeonholers, slotting people into tidy categories to keep things simple; unfortunately it doesn't work that way, and it doesn't keep things simple, either -- we've seen how many will pounce on someone for having accepted the label of "bi" but then later saying, "I really am gay" for hypocrisy, when the sensible thing to do is to give affirmation in progress in understanding himself.  For lots of guys who see themselves as bi, it's especially agonizing because they have no way of telling just how much attraction to females has been socialized/brainwashed in and how much (if any) is real.  Jumping on the person who figures out after a long while that he really is gay is not merely foolish -- though it is extremely foolish -- but cruel; the people to be jumped on are those who managed to program the person to be something other than his real self in the first place.
Guys need encouragement and support, not attacks.  It's bad enough that every time I see a gal who makes my breath stop and thighs tingle I wonder if it's really me turned on by her, or my programming; I and those like me certainly don't need grandstand coaches slamming on us for whatever bigoted reason they have.
So to those who love to pontificate as though they were a gay version of Westboro Baptist, I have this:
At least until you grow up enough to regard others as people.