I think there is a 3rd option -- the one I most always recommend -- between the A) ignoring and B) revealing your intel.
And that is, the next time she gives you the "just friends" thing, to put your hand up in the "stop" position and say "Please STOP IT. Just stop. We both know you're lying to me right now, and it's incredibly disrespectful not only to me and to our marriage, but to our family. Look, I know all about you and (OM's first name), and I have for quite some time, to please just stop lying to me -- it insults my intelligence, and frankly, it's not very attractive."
And then, when she presses you, do NOT reveal what you know, and never, EVER reveal the source(s) of your intel.
There are but a few cards the betrayed spouse holds, and one of them is that the wayward spouse doesn't know what you know, and what you DON'T know, so when you tell them you "know everything," they have to operate from a position that that is true.
I ultimately re-confronted my wife about her affair and I specifically honed in about the DECEIT of it all, and I did it this way: I said that if our marriage was indeed going to end, that we needed to be effective co-parents, and that I knew we both wanted what was best for our kids. And that we had ALWAYS told our kids that lying wouldn't be tolerated in our family, and you're not going to start now, with her affair.
And I gave her exactly five minutes to decide to tell her parents and our adult children the truth, or I was going to do it for her, and show them my evidence.
She opted for the truth, to her credit.
That's just me, Zew, and nit84 is right -- YOU have to live with the consequences. Exposing the affair is against DBing, but I don't really see this as exposing her affair to anyone other than THE TWO OF YOU -- husband and wife (still). If the two of you can't call a spade a spade at this point, how can you ever expect to effectively co-parent your children, if the marriage indeed tanks?
