It may be that you had no clue, that this came out suddenly and you were completely caught off-guard. I don’t know your circumstances, and don’t presume to speak to absolutely all cases.
However, if you have read the chain of posts, you will find that the wronged spouse in the case at hand is clearly aware that things are seriously amiss. I practiced divorce law for 12 years, so I hahve a bit more experience than you are aware of. I worked closely with psychologists when I could, to help my clients through the process. And I have not yet met a psychologist who has been involved with those expierncing the trauma of a cheating spouse whe doesn’t back up my experience that most wronged spouses sense that something is amiss, and many will do all they can to live in denial of what others can plainly see. I do not suggest you did; only that many others do.
I do not suggest that marriage is not permanent or that it should not be, nor do I suggest that people - wronged spouses included - should not work on keeping a marriage together. Some marriages do survive an adulterous affair, and I would not doubt that if people worked harder at it and had a greater committment to permanency, that some marriages that end in divorce over adultery could have survived also.
Ignoring the signs of an affair is one way of self-preservation; however, it is not an effective one. A wronged spouse who senses the affair and won’t admit it squarely and deal with it - e.g. counseling - is not going to listen to the adulterer’s co-worker who comes warning, because the wronged spouse is already in deep denial; they use the denial as their means of coping and will see the co-worker as a threat to their means of coping. I have seen it repeatedly; it is not like it is a rare phenomenon.
no offense, but who cares as to why victims of cheaters remain in marriages

…that’s not the question of the OP…the question here is should she get involved? And the answer is no, and she should also not lie for her boss.
My advice remains the same: unless you as co-worker have facts - you have caught them in pari delicto - all you have is hearsay. Volunteering presumptions, suspicions, and rumors is likely to elicit the response from the wronged spouse that you are part of the problem, not the solution. The co-worker needs to stay out of it unless and until the wronged spouse comes to them asking specifically if there is an affair going on; and then the co-worker had better be really careful as to what they say and how they say it. Until then, they are simply using a big spoon to stir a pot that is (most likely) already at full boil.
I didn’t “blame” the victim for the actions of the adulterous spouse. Read what I said again. This post started with an observer wondering if they should go to the wronged spouse and “tattle”. Nothing in my post says anything about blame. You have given no details of what happened to you, and you seem to presume that you would have had a different result if someone had only told youthat your spouse was cheating. That may or may not be, but I maintain that people reporting affairs to the wronged spouse are going to find in almost all cases that their injection of themselves into the matter is going to be at best ineffective, and may cause repercussions to themselves for doing so.