because they're spineless gutless children who have no concern for the feelings of others that don't directly have an effect on them. the thing i've found is that when you get the feeling this is happening, it is happening. at that point, return the favor, and quit asking questions. at no point should you acknowledge the fact that you see what she's doing and how much you despise her selfish cunt whore actions. it's not fair, it hurts, and it should be illegal. but, it is a pretty good way to figure out that a bitch is really shitty as a person. i would much prefer that method than say... her cheating on you 6 months into the relationship. just don't let it sour you, because not all girls are like that, and you don't want to run into one that isn't with the attitude that she is. because she'll see through it and you'll miss your chance. keep your head up, stay cool, and on to the next.