So I guess what you are all saying to some degree is that time is on my side. And during this time I need to reflect on who I am and the kind of person I want to be. I need to start living life for me and the rest will follow.
Seems so easy on paper.
That's a good way to look at it. Taking your points, yes, time is on your side. At times, it will feel like your enemy, but it's not.
On the self reflection, also look at what your part is in getting your M to this point. It's hardly ever one person. Figure out what your part was, address the things you need to fix for you and then fix them. The key is that you are making these changes for YOU. Not for him and not to save your M - two things you do not control.
Start GAL'ing (get a life), meaning, do some things you have always wanted to do but did not have time. Things that don't necessarily cost big $$, but that make you happy.
And the "rest" MAY follow. One of the hardest things is to go through this process with no expectations. You will have them, but you have to put them away right now. Otherwise, you are setting yourself up for a big disappointment at the first time something doesn't go the way you had hoped.
Read a lot of posts here, especially ones that are similar to yours (Yes, the situations here are all very similar).