G - try to relax a bit. This first session will most likely be taken up by the mediator telling you the process. Nothing gets set in stone. They may kind of get a feel for how you both see this working. But again...nothing is final until you sign it. You can always change your mind on things before that happens.
What you do not want to do is to go into this with a chip on your shoulder or defensive and blaming her or expecting X,Y and Z. As you said - keep an open mind. The best way to get what you want is by NOT demanding it. If you start making demands and getting agressive it will just put everyone off and make them get defensive.
This DBing 101. DBing is more than just trying to save Ms. It is about interacting with people and influencing them. Use what you have learned to get what you want.
Sure maybe it didn't save your M. But would you have had any chance at saving it if you had started demanding that she do certain things? Of course not. Be smart and stay calm.
