I'm not an expert at all, but I do know that I exposed the affair to my WAW's family, and it didn't change her actions one bit. This was pretty much right after I found out, and asked her to leave the house. I made a lot of mistakes that first month, but I'm trying to learn.
I would agree with Starksy you should have the talk where you tell her you know with the hand etc, but just remember that there is a high chance she will not change anything she is doing. She just won't care enough to change her behavior.
Obviously, you've been thrown for a loop, and much like myself, feel the affair is a f&$&$ing major stumbling block for the WAW to move past and start to realize what they are losing. It's like relationship Disneyland to have a M and cake eat and then have an A on the side. So I would surmise that we tend to focus our efforts on ending the A, because we think that is the only problem. What I'm starting to realize is that even if my W ended her A, I'm not sure she would chose to even attempt a R again with me. But that's out of my control and same for you. We need to keep working to continually improve ourselves so that we are ok no matter what happens
Exposing the A will not change her behavior I don't think, because it sounds like she is in denial anyways. She will just not talk or avoid people that know. She will justify her A however she needs in order to maintain her relationship, utilizing "evil zew". Don't give her that chance by focusing on yourself, so easy to say and yet so hard to follow.
