I know this hurts, but once you guys agree to D, there's really nothing you can do about this. I had a bit of a "post-Cold War" feeling of emptiness myself, having fought SO hard to bust up my wife's affair, that once I filed for D two years ago (we've since reconciled) I suddenly realized I really didn't get a "say" any longer in where she went or what she did.
And she, having to no longer hide it, was freer to operate as well. All you can do is lay out whatever few boundaries you still think you can enforce, and move on with yourself.
