I’m very upset that my married friend/neighbour used my name to lie to his wife about his affair.

His cheating became obvious when I learned that he’d told his wife that I’d been present when he was “out with the guys.” She commented to me about it a few days later when I saw her, and she’d asked about the restaurant’s food.

I called my friend at his work and he tried to brush it off, then confessed the affair when I persisted.

What do I do with this information? I like his wife a lot and she’s expecting their first child. His deceit sickens me.

But if I tell his wife, she may leave him and have to raise her child on her own, possibly dealing with him and his lover. Or she’ll stay, never trusting him again.

Do I say nothing? How do I end the friendship with him without her asking me why?

Speak Up?

Periodically, this dilemma reappears in the column: Do you OUT a cheater? Interestingly, whatever my answer, readers’ feedbacks will include all of the above choices.

Another, however, is to tell this guy that, if he doesn’t end the affair and work on his marriage, you’ll tell his wife that he was not with you but out with another woman.

Not your business? Here’s what I’ve heard from those who matter most - the people cheated on - whether it’s a wife, husband or partner, and across the genders:

They write of feeling betrayed not only by the cheater, but by those who knew and said nothing.

A typical example: “If I’d known, yes, it would’ve still devastated me at first, but since I had to leave and start over again, it would’ve been easier if I had support from my two closest friends.

“When I learned that they’d known about it and said nothing, I couldn’t be friends anymore.”

Or the man who only discovered the lies two years after his partner’s affair had begun with a co-worker where the couple both worked.

He was so angry at the other co-workers who knew about it and stayed silent, that he quit his job.

Adding this choice doesn’t make your decision a lot easier, I know. If you tell this man’s wife that he’s a cheater, she may disbelieve you, and end the friendship.

BUT, you would’ve given her the dignity of a chance to decide what’s right for her, not what’s best for you. She may even eventually thank you. Or not.

Now, choose your response, soon.

FEEDBACK Regarding your answer to the woman, 45, worrying about her partner, 41, saying that their youthful image may be affected if she stops dying her hair blonde (January 3):

Reader – “I say DUMP the loser!! If he’s so concerned about her hair colour, then he’s not worth the time or effort.”

Signed Naturally Grey and Beautiful

Ellie – Thanks for adding this perspective!

Having dyed her greying hair since age 30, the letter-writer stated: “I’m facing a decision that I’m not sure I can handle in my relationship or my own mind.”

I focused on her relationship with herself and suggested talking to a therapist about re-assessing her self-described identity as a “Blonde Bombshell.”

But you rightly also focused on the flaw in her relationship with this man for whom a hair colour could change his feelings towards her.

I now say, Naturally Grey and no longer “itchy” from the dye, is far better than living with a jerk!

FEEDBACK Regarding the woman whose long-time partner, separated, still hasn’t divorced his wife (January 7):

Reader – “Since he has children, it’s likely he had a separation agreement regarding custody and financial matters despite no divorce.

“If he feels, as many people do, that he took a financial hit resulting from the marriage break-up, he may think that it's safer not to marry again.

“Even if he didn't take a hit, the break-up would’ve opened his eyes to what it might have cost had he not been lucky.

“It's a common fear of those who’ve gone through separation or divorce.

“Not being divorced, then, could be how this man hopes to protect himself from the financial fall-out of a second marriage break-down.

“That’s why his partner of 15 years should get him to a lawyer who’ll explain to him that in many jurisdictions he’ll have already incurred obligations to her, despite they’re not being married.”