The Betrayal

Is there any other more equal in betrayal than to revenge it by doing betrayal to the betrayer back?
“I trust men more than women in keeping secret. As far as I experience in my life, women have tendency to betray people, including their own good friend. They do that especially when they want to secure their own position in one case.”
A good friend of mine—a woman—said such a thing to me last night when I confided in her that a friend just betrayed me. I was a bit shocked when hearing it. How I always hate sexist opinion like this. Nevertheless, then I found the answer why she opined like that. I responded, “Well, living in this patriarchal culture, women were taught to consider other women as their competitors. For example, living in marriage-oriented society, women (especially) were indoctrinated that to be considered happy and “normal”, they must get married. In a heterosexual society, women must chase men to be their partners. It is unavoidable, then, if women consider other women as competitors. And in so doing, sometimes they cannot avoid the tendency to betray other women, for their own sake.
I was born in a very religious Muslim family where I was brought up viewing man-woman relationship is not good, only after “the right time has come.” I cannot avoid feeling uncomfortable to have guys as good friends. This made me feel more comfortable to make friend with women. It is different from my good friend who proposed that idea above. She has made friend with both boys and girls. Does it, then, make her know men’s characteristics than me?
Since I was a little, I have been taught to resign myself when having dispute, to have a quiet life. Of course I don’t have a heart to think that women—my folk—have greater tendency to do betrayal.
And I have been indoctrinated that if we never do bad things to others, we will not find who do bad things to us either. If we always do good things to others, we will get good ones too from other people. Well, perhaps it is similar to “karma” in Buddhist.
Therefore, when a good friend—who once claimed me as her soul mate, as her place to confide in because I always understand her—betrayed me, I don’t have any idea how she could do such a nasty thing to me? I have never done bad things to her. (Or is it only my opinion, because in fact, I have once hurt her without my awareness?)
How tired and difficult it is to repress this pain and anger, and I realize how I really want to take revenge to her, to betray her directly, and not wait for “karma” or God to do it for me.
Ah …