Sorry that you find yourself here, but you'll find no better group of people to get your M back on track.
Karen is right. Stop giving her things to read. You need to change YOU.
"does anyone have any advice or success stories for people who were in low conflict marriages and are in an ILYBNILWY as most of the DB book that I am reading seems to focus on marriages where people argue or where the H is emotionally withdrawn from W?"
There are many. What you don't seem to grasp is that if your M had gotten to the point of D, then your M is high conflict. YOU may not perceive it to be that, but your W does which is why she wants out.
If the two of you don't argue and have just "lost that spark", there are ways to get it back and PHEA was a great, TRUE example of a woman who made it a point to get it back. Your W was missing the point because she doesn't want to.
You need to really give us more info about your M and the relationship in general in order for people to be able to help you better. You can do it.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.