Well I'm afraid I can't really help on the destructive coping thing, my own most destructive behaviour was becoming addicted to isolation, a natural intraversion gone too far to the point where I wasn't seeing another person for a solid four or five days.
As to letting people down, that sounds familiar. when you walk around with a sense of worhtlessness spo profoundly part of you that it becomes as central to your being as hight or weight, being asked to do soemthing by another person can be a real and distinct buz sinse it gives you a sense that you are! in some sense important that you can't feel yourself.
Weerdly enough, I've always found myself that it is far easier to care about and do things for others than it is for myself.
For me, the answer to worthelssness was not to confront it. I learnt to recognize firstly that it was entirely not! my fault, be a consequence of what I! happened to think, rather than a literal truth, and secondly that my own over crytical idea of myself was due to an entirely flawed way of thinking.
I learnt to regard myself as my own worst crytic, and therefore treat anything i thought of myself as the unreasonable expectations of a heavily biased person. In the same way that I wouldn't listen to the opinions of someone who had some sort of irrational prejudice against me, ---- say because I was a man or was caucasian, I would not take into account my own opinion.
For instance, I recently finished my doctoral thesis and handed it in. I myself think when reading it that it is entirely and completely bad! and is bound to be marked as a failure simply becuaase I! wrote it. However I realized that my tutor, who I deeply respect and know to be a very accomplished and wise man wouldn't have let me submit it if he didn't think it was worth submitting.
Therefore I take his! opinion over my own, because I know his opinion to be none biased. ]]these sorts of changes in judgement however only happened after I'd been in recovery for a bit, gone through the despression and the isolation and the nightmares and everything else.
One other major problem I found with recovery, is that unfortunately the bennifits aren't really things I could've known about when i started.
I originally thought recovery would help remove my genophobia, help with the relationship thing, stop my sense of worthlessness. I became quite frustrated that none! of these things had worked, especially as regards lack of any sort of relationship at all (something I still find difficult sometimes).
However it's only more recently I've started realizing that recovery is a process of acceptance, of being able to say as you said "this is my normal! nuts to everything else" but that wasn't easy.
Of course, all these things are just my personal experience, and those of your husband might be very different, still I do hope you find some tof this usefull, and I really hope things get better for both you and your husband.