"I resisted my W's efforts to get me to leave the MBR but maybe I should leave for my own sake? Is that a good idea?"

Why not suggest she leaves the MBR?

"Walk away spouses also continue to try to draw their spouse into the drama. At least until they feel emotionally and financially secure to pursue their fantasy"

As A WAW or WAH struggles with their choices, they feel the need to dump on those closest to them. That be you.Also, once they feel emotionally and financially secure, you are no longer need as a provider of anything. Except a weekend babysitter perhaps. Is this true of all? No. Most? Yes.They are inherently selfish at this point.