I remember following your situation back in Oct 2008 when you were going to confront the A at a hotel in Chicago.
Because of your continued emotional riding of the rollercoaster and your husbands continual cheating, cake eating and lack of respecting boundaries, I have to agree with Greek - get that big legal gun cocked and file for a D.
But keep in mind that a D can take a while to process. During my year going through the D, my W was at times on the fence and right before it was final she asked for another chance. I had realized, during that time period, that she was a crappy selfish bitchy wife and I said no and let the D become official. She is now married to her affair partner who is 31 years older than her.