What's your stance?

My girl friends and I were having a discussion regarding fidelity in relationships.  I was surprised to hear that everyone had a difference of opinion on the topic.  Most would certainly agree that being faithful in a relationship is imperative, and the only moral way to be. No argument here - but the question of how to handle things is really where the roads diverged among us.

Let me explain: one of my friends said that if you ever have a once-in-a-million situation where the stars-aligned and you found yourself in the unenviable position of having cheated on your spouse/significant other, you should NOT tell them.  This was a somewhat surprising outlook to me.  Honesty is harped as one of the most important aspects of a healthy relationship, followed closely by communication.  The concept of keeping such a secret goes completely against both of those rules of thought, however, for the sake of this post - I would like to explore this idea.

My friend's perspective is one who has had a partner be unfaithful, and was hurt immensely in all manners of measurement.  The toll was not only emotional and physical (being single/alone) - the financial fallout was off the charts as well.  So clearly, my friend is speaking from experience.  The backing for her argument to remain hush about it is that telling your partner what you've done is selfish because the confession was likely brought out by your own guilt, and not because your partner deserves to know the truth.  If you did the deed, pay the price by suffering with your own regrets in secret rather than drag your partner down with you, my friend says.  I might be inclined to agree with her.  

That being said, is it better to be in love with someone who was once unfaithful but discreet?  Or is it better to know about it, even if it was only one time?  Will knowing the truth dissolve a good relationship over one slip-up or can a relationship recover after a period of healing and reconstruction? Frankly, it might be better to just stay blissfully ignorant to your partner's transgression. 

Obviously, repeated infidelity shouldn't be tolerated because it puts you, your partner(s) [and their partner(s)] at risk. Some would debate that monogamy is simply loving the one you're with RIGHT NOW.  Apart from the poly-amorous, people generally feel that spreading oneself around denotes a lack of emotional value/respect for yourself (particularly if you're a woman) and for your relationship.  Many cheaters would say otherwise, but they are simply filling their own selfish desires, and not taking into account the needs of their partners equally with their own.  I'd say that most would agree that if you truly love someone, you wouldn't risk hurting them (or worse: passing on an STD) by being unfaithful.

I'd be interested to hear the perspective of men on this topic.  I wonder if a woman's outlook will differ from that of a man's.  Do men feel more possessive over their partners, and thus, less tolerant to cheating? Or conversely, are women more insecure in their relationships because men can have a reputation for "spreading their seed"?  I think it's safe to say that the answer to this difficult question will be different depending upon not only gender, but the personal experience and the belief system of each person.