The folks reading this blog may or may not know how Jaimie and I have walked through her struggle with clinical depression over the last three and a half years. You can find some of our story, and - more importantly - some of the huge lessons I learned about walking through a spouse's depression in this new post at Ardent Fidelity:
You are not the hero of this story. Jesus is. The sooner you get that, the sooner you'll have any chance at all of really helping your spouse in this time.
The hard reality - and the good reality - is that, much as we want to, we cannot fix our spouse's depression. No words, no encouragement, no number of chores taken up on their behalf will do the trick. There is no switch to flip, no magic incantation to take away the darkness. That doesn't make those things meaningless. Your spouse needs every bit of help you can give. But operate with no illusions: you will not make your husband or wife better with those actions.
This is freeing, really. You can simply do your best every moment, and trust that God is bigger and greater and capable of doing all you cannot do. You can't carry her; don't try. Do what you can do.