Confront her about her affair?

[Astimegoeson]

I concur, you need to confront her, not an ultimatum, not out of anger or in a judgmental tone. Calmly let her know your aware of the affair and you are not OK with it. Let her know you love her and want to work this out and that you will patiently wait while She makes her decision, but that you are not willing to be second best to any Man. To this point, She doesn't really have any motivation to even think about stopping the affair and working on her marriage, this dimension at the very least needs to be introduced.

How could a Woman expect a Man to stand up for her if he's not willing to stand up to her? It shows your not weak and willing to make a stand on your principals. So what if you loose in the short term (she leaves)? She will respect your character in the long run and that's probably the best you can hope for at this point.

If She's going to walk out on you, she'll do it whether you confront her or not. If what you say about your lack of intimacy for so long is true, then you need to get the ball rolling now if you expect to save your marriage.

Every situation is different and you ultimately have to decide for yourself what to do or not do. I don't know all the variables in your situation. I'm just giving you advice based on the pain that I've gone through. I've done things wrong and I've done things correctly. I can say that confronting my W was the first step in enabling us to at least communicate about our marriage and the issues involved. You will discover a little more openness on her part once she knows you are aware of her affair. You will actually discover a lot of things about your W you never even thought of once you get her to open up to you. You have to remove the secrecy and really start to re-discover your W.