I'm not so sure about everyone being pro M, I think it's more like pro choice.. Rooting for the LBS to make the decision on remaining M from a distance, through rational thought and desire.
For me, I hope everyone who wants to save their M is able to, but only if they can do it through an acceptance of what has occurred and an understanding of the work ahead to build a healthy and generally happy MR. The way I see it is if I found another person I wanted to be my W, that R would also be a lot of work, so for me, the key element is trust and desire.
Can I trust that my WW is committed to a new MR with me, can I trust that she comprehends the seriousness of adulatory and wouldn't stray again during the bad times (there will be more), can we desire each other enough to stay together in a M for the next 40 or so years. Can I trust that any decision I make is fully thought out, and that I comprehend the impact it will have on me over the next 40 years. If I leave, do I fully believe I will know I made the right decision in just 3 years?
You went from wondering if you should let her back in the MBR to D in the span of 4 days, I know when I make those kind of swings I'm coming from a place of emotion, so I would just caution you to take your time in making a big announcement. Go forward for the next few weeks with the mindset that your going to D, go dark, stay away from her, see if your happy with that decision over just the next few weeks. If you waiver over the next few weeks, then your probably not ready to make that decision yet.
I understand the desire to cut the cord and put this past you, I'm right there with you, I've made that "decision" a few times, only to change my mind the next day. I fully acknowledge that I don't know what I want, well I want this to have never happened but that's not an option, so for now I continue working on me and us. What will be will be.
Ps, it was nice to see everything you gained from this, and no matter what happens going forward, you will always be a better man for it.
M - 9 1/2 years 5/5/16 - Bomb drop - 3 week EA 10/31/16 - We sold house 01/10/18 - D Finalized