Being married also to a man who suffers from depression, I can totally relate to much of what you are talking about. I've so been there in that "I'm done" mode. And my husband has help via medicine, but refuses to get other therapy. I know it must be doubly hard with a child also in the mix, but all I can say is plug along and know that it is not you that is the problem. Kudos for you for sharing this honest and deep part of yourself!
Wow! This is very powerful. I have suffered from depression for many years. Thank goodness, I have some good medication that keeps me from that dark place your hubby goes to. It's no way to live - trust me, I've been there. Nice job.