Tad, I'm not giving you any 2 x 4s here--it's not that I disagree with anyone above at all. It's that for you, you were pretty low key here--you said a lot less than you usually do. You defended a bit, yeah, but you didn't jump when she said lunch. For you, that's pretty huge. So congrats on that :-)
Understand that the chances are VERY good that she will go through with all of this. Most of them do. You let it play out, and you protect yourself. That's all you can do.
I think the lunch thing has to do with her trying to make it seem like it's all hunky dory, all just "ok", as if you both wanted this. If you want to have lunch with her and you really think it's a good thing, go ahead. But if you don't, then don't. I suspect it won't go well if you do, I mean, how can it? It would require you to act like you wanted the divorce to keep it from getting contentious, and you don't. So have a plan for something else to do. Take your kids out. Take yourself out. Call it a "making the first steps in my new life" event. Whatever it takes.
So...you're looking at October for the date. What are your plans between now and then to make your own life the most empowered life it can be? That needs to be your focus. Your job isn't starting for a few weeks, right? What are you doing to keep busy, besides celebrating Little Friday? :-)
M45 Bomb 6/09; EA 6/10; Divorced 1/11 Proud single mom of 7 little feline girls and one little feline boy "Fall down 53 times. Get up 54." -- Zen saying