When counselling a friend who was considering telling her boss his wife was sleeping with another man, a wise character in episode two of the new television series Devious Maids dispensed the following advice:
"Once you tell someone that the person they love is cheating on them, you change their life forever."
I used to be very black and white about this issue: if I knew for certain, I'd consider it my duty to ensure the victim was enlightened about their partner's extracurricular activities.
But it's a strategy that can backfire. Not everyone is grateful to receive this information. Some people think ignorance is bliss while others are inclined to blame the messenger for interfering. These days I'd be much more conflicted about whether to pass on such news.
In fact, if you read Help! Should I tell My Friend that Her Husband Is Cheating on Her?, a story with the subheading "Principles to Consider Before Confessing News that Could Ruin Her Life", you'd probably keep your mouth zipped no matter what damning intelligence you possessed.
Described as a "relationship strategist", the writer paints a gloomy picture of delusion, misplaced loyalty, inertia and defensiveness - all but indicating that divulging the truth is likely to be fruitless.
A wide cross-section of attitudes was revealed in the comments. There were wives who said they'd want to know if their partner was cheating, people who advised writing an anonymous note, others who fancied confronting the cheater instead and those who thought people needed to mind their own business when it came to others' affairs.
One wrote: "If I found out that my friend knew my husband was cheating and didn't tell me, I'd dump that friend as well as my husband." Another said: "Pretend you never saw it and move on." It's a subject that polarises people.
The writer of Should You Tell Your Friend That His or Her Partner Is Cheating?, who frames the dilemma in ethical terms, says "moral decisions are not always easy" and decides that "I would ask myself, 'What would my friend want me to do?'".
I've never encountered anyone who says they'd rather remain oblivious to a partner's straying, yet the old saying goes that the wife (or husband) is always the last to know. That implies the existence of a conspiracy; not only is the partner cheating but friends are effectively involved in a cover-up. The victim has reason to feel betrayed on several counts.
In What a betrayed wife stands to lose by being the last to know it's revealed that the "longer the affair goes undetected, the more time the cheating husband has to bond with the Other Woman, and the harder it will be for him to end the affair".
This writer, an "infidelity expert", also says there are potential negative financial consequences for an uninformed wife: "A cheating husband who's planning to leave his wife for his mistress, may start liquidating marital assets behind her back prior to asking her for a divorce". There are also health issues: "If her husband is having unprotected sex with someone else, she's at risk for HIV/AIDS and a host of other sexually-transmitted diseases."
Why Elin Nordegren was the last to know about Tiger Woods' affairs says that modern technology, complicit friends and frequent travel all aided Woods in his cheating as did his wife's unconditional trust, failure to recognise the signs of infidelity and preoccupation with the children.
When you consider the extent to which the deck is stacked against the innocent victim in a love triangle, it's difficult not to be inclined to put her (or his) interests to the forefront. If knowledge is power, then surely the more they know the better. And ultimately it's up to them as to what they decide to do with that information.
Have you ever discovered a friend's husband, wife or partner has been cheating? What was your response? Would you want to know if you were the person being cheated on?