A GF divorced her H b/c he was a professional student and wanted to hide in academia as a student. She was the primary breadwinner. He really didn't show any indication of wanting to grow up and enter the real world. Was very comfortable going to school forever on her dime. Sounds like W has been waffling with school for awhile - well sounds like she lacks the ability to commit and follow through on long term stuff in general.
My last BF before The X sounds a lot like W. I dated him on and off through law school. He did the push/pull thing. For example, invited me to meet his mother. We drove to her house for the weekend - he broke up with me while I was there. He would date other people - I would move away and date other people - and he would come back. I got tired of it after 3 years and didn't even tell him where I was going when I graduated from law school. And when he knew I was done - he pulled the hardest. He really did break my heart - but I really just didn't see a future with him b/c of his behavior.
I think you are handling things perfectly. I think you are right - W will be all over the place over the next few weeks with the approaching D. Let her go. She is only appreciates what she has when she is faced with losing it. And really who wants to put up with a lifetime of that crap.
I would love to hear more about Israel and what you did there when there are less pressing issues on your mind. I am a travel junkie! And you were there on a dig - how fascinating! Are you and archeologist? You don't have to answer if you want to keep your profession off the BB.