Hi Future, I've wondered about the throwing the stuff on the front lawn approach too, and whether that would have been more effective. It might have been. But its probably not far enough...like drinking or doing drugs, the OTHER person has to feel like they've hit bottom, I think, for that to work.
My XH was extremely depressed at that time--and I know he is still very depressed. The slow reality of his life alone and with OW is catching up with him. Maybe a fast reality would have been more effective--I don't know. But I think he would have ended up "drinking" in secret, like your W. Setting up everything to continue living a double life. The rush was just too much.
In the end, I feel like you have to walk away feeling in your heart like you did everything you knew how to do to keep your family together. Future, from your posts and your ongoing saga, you have done everything you know how to do. Maybe its not perfect, but it seems like you've tried just about everything you can think of. I think at that point, its not the "trying to think of something else" that will change the situation. You've got a W who is entrenched in her own issues. She doesn't want to lose you or her family, but she wants to "flirt" and date other men. She needs that rush. That's really not compatible with commitment.
P.S. I think for the kids' sake, the "wishing" isn't good--i.e. telling them you wish you were at DW. It will give them the idea that people don't control their choices. Its probably confusing for them. If you wish you were there, why didn't you go? Either--"I'll take you myself sometime" or "You and me will take a different trip together sometime" might be a better reply.