Her behaviour may just be a very bad reaction/MLC/mental issue.
Try to find excuses to understand, while resonable boundaries to protect.
LSG,
Sometimes I found that the WAS "protect" their affair and "protect" their phisod behind it. That means YOU are an enemy to the affair. So as long as she's involved in it, she's working against you. Keep in mind, sometimes it may be logical for bad things to happen to us.
I wanted to say, some of us DB'ers in area's close to each other may as well visit each other for support. I know how isolated it can feel, and after your local friends have heard your problem for so long, they might not want to hear it any more.