So yes, you are getting a lot of the script, and you are able to see a progression from "things are OK" to "things are worse than bleak."
It is going to be up to you to navigate the negative spew and re-writing of history to find any valid issues your H might actually have.
So it will be up to you to first detach emotionally from those negative things he may say or do. And also, think deep and hard about what may actually be valid or how your H may have began to drift away that were a result of your behaviours. Those are things you may want to work on as well as other things that you may think about yourself, that you may want to be better at.
What might some of those things be?
Also, GAL would likely be very beneficial to you, at this time. Even though you may not feel like doing any GAL activities and are otherwise consumed by thoughts about the troubled M, eventually you have to keep getting up and moving forward, for your own benefit, even if the M isn't saved.
What kind of GAL activities might you want to or consider doing?