Each situation is different that requires a different set of actions. It isn't always a one size fits all.
In your situation, you were engaged and ready to get M. So this requires a different set of responses. You need to remind W about the good times, your good qualities, and that you're the real catch here. I'm thinking W is taking a step back and re-evaluating her view of marriage in general which, to me, is a good move on her part.
Marriage is a huge undertaking and one needs to be absolutely certain about jumping into it. You two have had one failed marriage so it requires some sensitivity on both parts for you certainly don't want a second divorce on the Life Tally sheet. Right?
