You avoid this dinner because what you are doing IS working.
She is the one who brought it up after you agreed right?
That means keep agreeing with what she said she wanted. A divorce.....
Why? Because it is working. Not only that, but she also told you she was getting the rest of her stuff in the same sentence that she said she was going to ask you out. Don't miss that part of the conversation.
You may be getting tested here to see if you really meant what you said. The best way to show her you meant it is to let her "feel" that it is now YOU that wants this too.
Don't worry. If she changes her mind and really wants you back she will let you know it. This was only a start. You are on the right path, but will get veered off if not careful here. Don't settle for crumbs.