@jsku "All women who stayed after discovery - and are dealing with the pain of memories and flashbacks - would tell you they’d rather not have known.
And they are the majority. Talk to counsellors - they will tell you that when people have young kids, more often than not the marriages don't break up after discovery - men tend to not want to leave. Women stay and suffer through it."
First, there are many women who do not stay after discovery: not telling these women that their H is cheating means that you collude with the cheater in keeping these women in the dark. That's pretty immoral.
Second, if a woman finds her H is cheating and then realizes that people knew and didn't tell her, that can be really shattering too. It can destroy the woman's trust in society. She feels that no one was looking out for her, everyone was just watching this horrendous humiliating betrayal and not caring enough about her to do the decent courageous thing and tell her.
Third, counsellors may indeed see many women who decide to stay with their cheater and wish they had never found out. But in line with the first point, this is only a subsection of the cheated-woman population. Also, these women may think they regret that they found out but that's a defensive mechanism that temporarily protects them from the full horror of the truth. In time, and with good therapy, they will realize that what they really regret is that their H cheated and betrayed them. That realization is what will help them heal.
Fourth, if the betrayed spouse doesn't know about the cheating, that doesn't mean it is a victimless crime. It is very common that betrayed women know something is afoot, but they can't put a finger on it. They trust their H so think that his distraction or odd behaviors or irritability are her fault. The cheater brushes off her concerns, or worse, weaponizes them to extract more sex or nice things from his wife. So the wife continues living in this confusing limbo, trying to ignore her gut, which is increasingly shouting at her. What happens when you live with cognitive dissonance? It creates an unending subterranean rumbling anxiety that wears on you physically. You start grinding your teeth, feeling fatigued, getting abdominal and heart and other physical disturbances. Some women lose their hair, or gain/lose weight. The GP runs tests and finds nothing wrong. The woman remains in her miserable limbo, feeling like shit, wondering whether she's got cancer, and meanwhile thinking it's her fault that her H has become mean or is constantly grumpy or does odd things. Many women find that their stomach pains and headaches and fatigue disappear after they've left their cheater and have started to heal.
Fifth, many cheating men don't wear condoms. It's actually amazing how many don't. They recklessly expose their wife to STDs, sometimes they go straight from the OW to their wife without washing because it turns them on. They also expose their wife to vaginal infections and bacterial:yeast disturbances that upset her vaginal ecosystem and cause recurrent UTIs or intractable BV. I once read a Chump Lady article about what was better when a betrayed spouse left their cheater and it was stunning how many said independently that their chronic/recurrent UTIs and BVs suddenly cleared up. (Along with their headaches and bloating and bouts of racing heart - see the 4th point).
Sixth, not telling a woman that her H is cheating means that she will continue to invest herself in the marriage. She may have more children, and thinks it is safe to not prioritize her income-earning capacity. This woman - who could have learned about her cheating H after child #1 and taken steps to protect herself financially - is then completely blindsided and on financial rocks and facing a penurious old age when at the age of 50 she is abandoned by her cheating H because he's "fallen in love" with an OW. This is actually not uncommon: we recently had a thread here of the OP and her children being abandoned by her H, who went to NZ to be with his OW.
So yes, I think it is irresponsible - if not to say cruel - to not tell a woman that her H is cheating. It's also utterly patronizing. And it probably more stems from lack of courage that is masked by a lot of self-satisfying rationalizations than really wanting to do what is best for the poor woman.