Your post jumped out at me, and you'll soon see why. 5 1/2 years ago, my wife had a brief (but intense) affair with her . . . personal trainer! And he was 19 years younger than her.
You're in a tough spot. You DO need to confront your wife, and you DO need to establish some healthy boundaries for yourself. But you're NOT going to be able to control her (nor should you desire to), and you're NOT in a position to be issuing ultimatums to her. Think of it this way, you'd basically be saying "This is what I need in order for you to stay married to me!" and she'd be like "Who says I even WANT to stay married to you right now? I told you I'm no longer in love with you!"
