Hugs mama. It is hard to live with someone who is depressed and anxious. Is your dh in any kind of therapy or under the care of a psychiatrist? I know for me getting in therapy and under care of a psychiatrist to control my meds has helped alot.
As someone who suffers from anxiety and depression, it sounds to me that his symptoms are medicated but not well managed. When my meds are really working, I'm not anxious or depressed. I've just had 3 weeks where, for no apparent reason, my meds stopped working, and it was hell. I'm slowly climbing out of my hellhole, but I've had to ask for a lot of help (when I normally don't).
I would ask him to keep a log of his anxiety. Something like The Anxiety and Phobia Workbook might help him get started.
Then I would drag him back to the psychiatrist and ask to be part of the meeting for a bit. It's very easy to minimize the symptoms (one of the things that kept me from getting help when I first needed it was my ability put on a good face for the doctor). so, if he has a log of symptoms and you have your insights that you've posted here, it should help the doctor get a clearer picture.
If he doesn't have a psychiatrist, he needs one. If he has one, maybe he needs a new one. Not all meds work for everyone. He might need to add one, or switch over to a new one.
He needs to be in on-going counseling. Cognitive Behavioral Therapy is supposed to be the best for anxiety disorders, but if you suspect there are other reasons behind his anxiety, then maybe a different kind would be better. He needs to learn to set boundaries for his anxiety so they DON'T affect the whole family. You obviously know a lot about mental health, so maybe you can figure out together what kind of therapy would be best.
What is he doing to get himself better? Is he taking his meds as directed? Is he learning new ways to manage stress? Is he exercising? What's his diet like? Is he seeing a naturopath? Has he tried acupuncture? Does he drink caffeine? It's not fair to the rest of the family to continually make them responsible for him not being stressed. I've had to ask my kids to do a few things they didn't want to over the last 2 weeks (e.g., dd had to go to ds' soccer practice because a friend was coming to take me for a walk, and I wanted to be free to converse with her as she's been down this road). I've felt incredible guilt at not being able be there like I normally am for my kids. In the short-term, it's OK. If it were a long-term thing, I'd be in counseling for me and with them.
Since I've had my downturn: I quit caffeine (and my pdoc said I need to be off it for a while), I've started going for long walks 2x a day, and I've added protein to my diet (tons of it, as I'm craving it), and I've nearly eliminated sugar. I've gone fairly low on carbs overall. (During my worst week, I literally couldn't stomach carbs, so it wasn't something I did to be better, but I'm feeling like it's helping, so I'm continuing.) I may try acupuncture soon. (I know this is a natural family living site, but I can't get over my suspicions about naturopathy. However, many other people have had it help.) I've increased my meds, and added several others (not happy about that, but I need them right now). Right now it's looking like my old anti-anxiety drug just wasn't working and I need a new one. The good news is that the new one seems to be helping. I'm not holding myself up as a paragon. I feel pretty guilty about a lot of things. But I'd feel worse if I wasn't trying everything I could.
Finally, please remember that it's not YOUR job to make him happy. HE has to do the work that HE needs to do in order to get well. Is he really doing that? I've got a pretty heavy burden of guilt right now because I asked dh to cancel a trip he was really looking forward to. However, it was the right decision at the time. My goal is to get well enough that he CAN go on a trip with his sister in December or January. But it may be May. We'll see.
I think it's perfectly reasonable (especially since it's been going on for a long time) to tell him that he needs to do more work to get well. Anxiety and depression are treatable. There's a very small percentage of the population who can't be treated. Very small. You're maxed out. He needs to get his symptoms under enough control so that he can be an adult in the household. Personally, I would think that couples counseling and maybe family counseling should be in your future. Maybe he needs someone else to metaphorically whack him over the head with the fact that what he's doing is affecting his family.
ETA: I realize my post may sound a bit harsh on your dh, and I'm sorry. But I do want you to know that you're well within your rights to be angry and frustrated right now. It sounds like you need a new plan for him, so that YOU can get a needed break. that's really what I was trying to say in all these paragraphs.
A friend of mine had no clue about her father's depression and anxiety and just thought she was part of the problem. It was her push to tell our kids about it that has made a big difference. I do have to take a lot of time for myself lately as DH is not medicated right now. The meds were making him worse and so he decided to get off it all. It takes me making threats to get him to go in. I don't like doing that and It's draining.