LoneScout I think you need to seek immediate help.
There IS a way out of depression, many people have recovered. There is no reason why you can't do that also.

Your pain RIGHT NOW will pass. What about the pain your wife will feel if you take your own life? Would it be an easier pain to deal with? How can you know that the pain you feel right now is more than she would feel if you left her? I am sure you care about that.

If you keep fighting this, if you are determined to be better, there will be happier days.
Please seek help, it's so worth it.