There's no sense ASKING her to be truthful with you, because -- by definition -- all cheaters lie, period. In addition, it will make you look supplicating and weak at BEST, and controlling and accusatory at WORST.
Not a good way to go.
My advice is always for people to make ABSOLUTELY CERTAIN, first (and we certainly are here), and simply say "(Wife's first name), I know all about you and ________, and it needs to stop, now. This is completely disrespectful to you and to our marriage. When you asked me for space to be alone, I gave it to you. I told you MONTHS ago that I would only fight for you if OM wasn't in the picture, and I now know you've been lying to me about it. Sounds like we both have some important decisions to make."
And leave it at that. Definitive, declarative, and yet leaves you a ton of wiggle room (because you're not saying ANYTHING you're going to do specifically, right now).
If she tries to lie, and say the whole "just friends" thing, just put your hand up in the "stop" position and say "Please stop. We both know you're lying to me right now, and it's incredibly disrespectful." If she tries to say you're "controlling" (as in "You can't tell me who I can be friends with!"), simply agree with her and say "You're right, I can't. You're a grown woman, and I have no desire to control you. All I can do is tell YOU what MY boundaries are, and I won't be in your life as a husband or a friend as long as OM is in your life. That's just a matter of personal integrity with me."
And END THE CONVERSATION as quickly as possible. NO R TALK, NO DECEIT from her lips.
I'll have more thoughts later, as I feel VERY strongly about this. WHENEVER you're ready to do this is entirely up to you, Alk -- I just want you to do it RIGHT when you do, because . . . as we say around here . . . you only get one crack at this. This is truly going to be one of those life-defining moments for you.
