Good to see STBX is getting a job. Mediation will KILL you if she isn't working. You'll end up paying all of the freight.
What the hell happened to the woman you married? When did she begin to thing that marriage was just a sugestion for fidelity? She really sounds like she's sick. Sorry, but seriously. Frank_D who has been on these boards longer than me has the same situation as you, but he has continued to try to make it work. I think there comes a point where you have to stop being a doormat.
I'm sure you have, but have you ever told her this is just plain unaccepatble. Why is she angry that you want a divorce? I've never sen a cleraer case of when someone had to get out like you.