If it were me, and this is only my opinion, I would decide on a certain amount of time to devote to trying to get her kick-started. And by that I mean using everything you know about DBing, which it sounds like you are doing for the most part, but especially the going dark and 180. I wouldn't pursue AT ALL. And I would decide on 6 or 8 months, or even a year, and then make a final decision at that point either to end it or give it another 6 months, depending on how I feel and what is happening with her.
It is interesting she hasn't filed yet - it sounds like she is still wanting to stay in the marriage.
You need to decide at this point whether you can give her more time or whether you are done and can move on.
Maggie
Me:47 H:49 3 grown kids Together: 29 years Sep: 5/8/09