No.

Stay out of it - you don't want to be in the middle of that shit storm, trust me.

I would say no. stay out of it. You don't want to be the initial reason for all this pain.

Doesn't matter if you tell him or she does. He'll still probably be blindsided and devastated. I say let her tell him so she has to deal with the consequences of her actions and choices.

I say tell him! If he truly is your friend, he will appreciate your honesty. He may not at first. But when he comes to his senses, he will. Put yourself in his shoes. How would you like it if your friend knew something about your wife and didn't tell you??

If you can come up with some way of doing it without her knowing it was you.. perhaps.
Because this is something he probably want's to know.

Stay out of it unless it interferes with your life. Your daughter's frienship will be impacted negatively if you cross the line and so forth. Do tell this woman that she has put you in the awkward positon and that she needs to be forthright....

If the man is not your friend and you only know his wife, through your daughter's friend, then is it really your place to tell him? What if it backfires and the mother denies it?

No...she told you this in confidence...respect that.

if her mind is made up, isnt the husband going to eventually know anyway, sounds like there are problems to begin with, I'd bet a dime to a donut that he is aware of the problems...some things are better left unsaid...my two cents, good luck.

Personally, I would want to know, but it depends how good of a friend you are to this person. If it is an aquaintance, let it go and don't get involved. It may be more trouble than it's worth. I have been in the middle twice and it sucks.

Your daughter will also be in the middle. BUT....if my friend knew...I better know.

If it was my absolute best friend , and he had no clue , I would tell him.

And I would want him to do the same for me.

My best guy friend sent me a text message a month after I helped my GF move out of my house , said he saw her at some Art & Wine festival holding hands with some guy.
It hurt like hell , but I really appreciated him doing it.

does she know of your situation?If so, I couldn't imagine why she would ask you except to upset you and have you tell her not to do it.

As for to tell the husband? I would say if he is a real good friend of yours, it would be something really hard not to. If it was me and the husband was a close friend of mine, I would talk to her first. I would ask why she is looking towards another? I would ask, why she can't look for what she needs in her husband. Then I would have told her that she knocks the shit off with the FB dude and get what she needs from her husband before I tell him.

No one deserves to be played for a fool, especially if one is going around boasting about it and involving others in their deceit.

but thats me.

If he is a good friend then yes, but he probably won't believe you. I don't get why she felt the need to bend your ear other than to see if maybe you were interested in her.

Think about it. It's kind of a way for her to say she would consider screwing around without directly saying it. Tread lightly this whole situation stinks to high heaven.