Zew, I'll try to give you a longer answer later, when I have more time, but my SHORT answer to your "What should I do?" question would be to KEEP DOING WHAT YOU'RE DOING (although maybe with some firmer boundaries in place), but just remove ANY thought your wayward wife might have as to how long your "deadline" is.
If you keep doing what you're doing, give it say the rest of this year, but make HER think that your love for her is slipping away every day she continues on this destructive course . . . (and keep in mind, eventually it WILL, regardless of what self-imposed time limit you give yourself -- you won't be able to control how fast her deceit and lack of respect for you and your marriage will erode your love for her) . . . I think you have a shot.
I don't see you doing a lot wrong, I really don't. I know that's rough to hear, because you want some "magic button" you can push, but if I saw it, I'd tell you (as you can see to my frank response to your sermon, above! LOL)
