I feel your pain.
Detaching... I can only share what I've done.
This may sound harsh, but I took your title a step further.
I mentally separated "husband" from "man".
I honestly accepted that the MAN inside (whom I used to know and adore) is still there... but as a husband, he is an A and not ABLE To be a husband. So I stop expecting him to meet the requirements of a relationship. I fired him as a husband.
Eventually, that allowed some compassion. So he's no longer a husband, I don't expect relationship "acts" from him. Easier on me. As a man... he's a struggling human being.
I can't fix the man either. But at least I don't look at him with hate for not being a good husband. "he's not capable of being one".
Peace.