It's possible that work is not the problem - he may have become depressed because he is predisposed to depression, and work is simply the biggest thing on the radar.
I had lots of struggles at work for lots of years, to the point where I decided to change careers. In the process of studying for my new career I discovered that I am depressed and never knew... and probably had been since my early teens. All the times when I hated work, it was probably really me that was the problem - I had undiagnosed and untreated depression. I was flat, struggled with daily tasks, found no enjoyment in anything any more, had a short fuse, was grumpy and judgemental frequently - sound familiar?
It's great that your husband is seeking help - that's so important. As AGrace said above, it's really worth considering getting his GP in on the plan too - people often find medications in conjunction with counselling or psychological interventions to be more effective than either approach alone. It might only be for a temporary period to help him out of his hole, or meds might be needed longer term for him to remain healthy... they aren't anything to be afraid of. If you need them you need them, if you don't you don't.
There are lots of things my wife struggles with about my "new" diagnosis (it's only been a couple of months); I think that's pretty normal and maybe you do too. Don't be afraid to talk about your feelings too. I was glad to hear my wife sharing her mixed feelings about it.
