I would strongly advise NOT to try to do this without your own attorney, no matter how amicable you two are. I have no problem with (and tend to like) using a mutually-agreed-upon mediator, and meeting amicably with them to try and hash everything out, but then I strongly advise people to either retain or just pay hourly their OWN attorney, to review the final document and advise you before signing anything.
Just wanted to throw that out there.
I'm sorry for this news, I know it stings. Anything can still happen, though, although you will need to hear and respect her wishes right now.
