This is a very difficult part of this journey - when they have "made up their minds" and there doesn't seem to be much hope. You've said what you thought about things being fixable, but it didn't sway him, right? I don't know that there's anything else for you to say at this point. You have to let him be, and if you want to show changes, do so through your actions, not through promises and talk. A quote I find helpful from "The Happiness Trap" when I feel stick on "but why won't he just TRY? These things are so fixable!" (emphasis added for the takeaway point):
"Suppose you are walking across ice. In order to safely take the next step, you first need to find a firm foothold. If you try moving forward without doing that, then you're likely to fall flat on your face. Acceptance is like finding that firm foothold. It's a realistic appraisal of where your feet are and what condition the ground is in. It doesn't mean that you like being in that spot, or that you intend to stay there. Once you have a firm foothold, you can take the next step more effectively. The more fully you accept the reality of your situation - that is, here and now - the more effectively you can take action to change it."
I find that repeating to myself "I don't like it, this isn't what I want, but I accept that this is what is" can help. I also try to reframe it as being respectful of H's opinion and wishes (as opposed to arguing, trying to convince him otherwise, or tell him he can't really be done, that it's silly of him to think that), which is a 180 for me.


Me:30 H:29, no kids
T:12, M:4 (when D was final)
12/13: "Don't think I want to be M anymore"
6/14: Separated (I move)
1/15: H filed for D
5/15: D final