You can't ride two horses with one behind. Since you have both agreed to go to Retrouvaille, can't you both stop the talk of divorce until you do the weekend? The weekend gives you lots of time to think individually and together. I'm not saying that it will definitely make your mind up for you, but when it is over you will have a lot of new information and new feelings. And then you can think on this again.
Pursuing divorce, talking to lawyers, hardens your feelings. Going to Retrouvaille and talking about feelings does the opposite. So why would you spend the 6 weeks leading up to Retrouvaille creating obstacles that you will then spend the weekend breaking down?
Agree to disagree. It's 6 weeks. You have agreed to go. So for 6 weeks, you just get along. You cook, clean, take care of the kids, work, talk about the kids, the weather, etc... and you let this wait.