02/06/2012 06:25 pm ET Updated Apr 07, 2012

Cheating: Do I Tell My Friend Her Boyfriend Has Been Unfaithful?

I found out through the grapevine that a boyfriend of a friend of mine recently cheated on my friend (with a hooker in Las Vegas nonetheless!). After much deliberation, I've finally decided I am not going to tell her.

I feel a bit like a traitor to my kind and I'm left wondering if there is some sort of girl code that should compel me, as a woman, to reveal what I've heard to my friend, another woman.

As much as I love my current boyfriend, I have girlfriends I've known since nursery school, and it's pretty much a sure bet that we'll be in touch till we're all in nursing homes. I hope I will get and stay married forever, but divorce is a scary threat for anyone contemplating marriage these days. In contrast, I know I'll never "divorce" my girlfriends. And yet, I've never taken any vows to them. I've never clearly delineated a promise to be faithful or forgiving or to sacrifice for them. So what do we owe each other? Is there an unspoken code that extends to all women and does it require passing on hearsay about cheating boyfriends?

Years ago, my then-boyfriend cheated on me and when he told me about it, one of the very first thoughts that ran through my head was how could another woman do this to me. I wanted to know who she was, what she looked like, what she wore, and what position she had sex in. There was a picture of my boyfriend and me that sat prominently on his dresser, and I asked him if he turned down the picture when she was in his room and he said no. To me, this meant the girl knew he was in a relationship and she slept with him anyway. How could another woman, someone I could have been chatting up at a bar the night before, how could she know that this guy was cheating and go through with it anyway? How could one woman be cruel enough and selfish enough to do that to another woman? But just because I understand how hard it is when a partner is unfaithful doesn't mean that it is my responsibility to expose all of the cheating men I come across.

It was painful for me to realize that even if there should be a girl code, there are so many women out there who don't follow it.

If there isn't a girl code, though, shouldn't there at least be a friend code? I want to do what is best for my friend. But is it in my friend's best interest for me to pass on an unsubstantiated rumor to her when she is desperately in love with a man who has continually been, in my opinion, a bad boyfriend? She's put up with poor behavior in the past, and I'm inclined to think she'll just make excuses for him again and believe whatever lie he tells. On the other hand, this could be the final piece of information she needs to finally break up with him. Also, I've thought for years that she should break up with him, so maybe I'm giving this rumor more credence than it deserves. It was passed through a number of people before it got to me, and nobody really knows what happened once the call girl and the boyfriend went upstairs, I suppose. I'm also reluctant to answer questions about where I heard the rumor because I don't want to expose my source.

The truth is, there is so much we don't tell people. What if I see a friend's boyfriend just flirting inappropriately? Do I then have to rat him out also? Again, I'm tempted to say yes, as women, we all owe each other the decency of collectively not tolerating cheating. In fact, the most unsettling thing for me is that even if it's best for her that I don't say anything, by doing nothing, I'm complicit in letting another guy get away with blatant cheating. Have we accepted infidelity to the point that that even if people observe the behavior in public, no one will tell?

I keep asking myself, if I were in her place, wouldn't I want to know?

I've been thinking about what the friend code entails: We have to understand, that by being close friends with another woman, we owe it to her to act in her best interest. To me, that means that even if we never say anything, we imply certain promises to each other: I promise to not go after a guy I know you like, promise to drop whatever I am doing and be there for you when you are heartbroken, promise to despise (or claim to despise) anyone who is making your life miserable, promise to not make moves on your boyfriend. I promise to keep your secrets, and I promise to tell you mine. And when in doubt, I promise to do what's best for you.

Although in most cases, what's best for my friend would probably be to tell her about the rumor, in this case I know it's not. My friend has dealt with cheating rumors with this boy before and chosen to ignore them. He's acted incredibly selfishly, and she's found ways to explain it away. And maybe it's not the healthiest thing, but it's also not my decision to make. She's the only one who can drag herself out of this relationship, and she can only do it when she's ready. When she finally deals with his behavior, I will be there for her during the heartbreak. Because as one friend to another, I owe her that.