I'm sorry you are going through this. I went through the same thing.
It seems like one medication fixes something and then causes another problem. So it's a roller coaster of which medications are causing what emotions. When he's taking one, he may be less anxious but more sleepy and lazy. But then when he takes something to counteract that, he gets hostile, snippy, etc.
The truth is, there aren't any artificial meds that will take care of his condition. Psychiatrists prescribe meds because they are told to, and the drug companies are making billions off of them.
There is a REASON your husband has ADHD and is depressed and it has nothing to do with a "chemical imbalance." The cause come first, the chemical imbalance comes SECOND.
That means, something in his life caused him to be depressed. Then his chemistry changed. It's never the other way around. Did you know that there is no "test" or medical proof of a chemical imbalance? None.
There are many therapies out there and many causes. Did you know food allergies can cause ADHD, depression and anxiety?
I went through the roller coaster for years, and unfortunately I have no advice to "save" your marriage. I got out, and it was the best thing I could have done. I lost some of the best years of my life to the unhappiness that the roller coaster of medications my ex husband took caused.
I am now happily re-married. I know your husband has problems, and you can support him if he WANTS to get better. But he has to want it. He needs therapy, not just meds. You are NOT a scapegoat for his emotional outbursts, whether he can control them or not. (He probably can't control them, but that doesn't make it right).
There is no "next med" that will work. They will just cause different side effects.
Getting him in emotional therapy is the only thing that will work long-term. He needs to confront whatever is causing his depression in the first place.
Get him to a natural doctor if you can. That really is your best hope. Through testing and supplementation, you might be able to find the root cause of his issues. I'll bet they are physical, and I'll bet it's a food intolerance, candida, or some issue that can be fixed.
Good luck, and I wish you the best.