I think Gettingby is one of the experts on this Reaching, but I will offer just a few suggestions:
1. Your wife should see a psychiatrist and explain that she thinks her medications may not be working. There are some new mood stabilizers out there now that are very effective in restoring the chemical balance. That could easily be the largest part of her problem.
2.. She needs to get back into counseling on a regular schedule.
3. Negativity is a strong signal that her chemistry may be out of balance. (The wearing of clothing that is black, navy blue, or purple can often be signals of a depression or approaching depression.) You are already knowledgeable about what to look for, though, so if you can persuade her to go to a psychiatrist and request a change of medications, it might be the key to turning your situation around.
4. She may need some changes in her diet: removal of caffeine and
alcohol if she uses either; they both make the illness worse.
I empathize with you and hope you are successful in getting some changes made that will bring you happiness. You need to be careful about your own health, as well. If the drag of her depression has gotten to you, you might want to get some counseling to relieve the stress. I think you have done admirably, but post traumatic stress syndrome can occur in a situation like the one you have. You might even need medication to calm you or help you sleep if you have a problem with that.
Take care of yourself.