I have read this thread for a while and I can't help but sympathize with everyone here.
Depression has been one of the constants in my life. I've always felt a sort of voice in my head, an evil alter ego, that permanently puts me down. It makes no difference whether I achieve some semi important goal or (more likely) how I fail at something. It's always there, minimizing my accomplishments, magnifying my failures.
My wife of three years is going away with another man. Ten years of relationship, three years of marriage, all gone because she was in love with another man while she was married to me most of that time. She helped me become more confident over time, and I helped her grow as a person (she was baptized a Jehova's Witness, and now is a Geology major in college). I moved out of state for her, so she could be with her family, go to the school that she wanted to go, and now she leaves me for an old love, who gives her something different that I offer, something that she yearns now as a 27 year old freshman in college.
I stopped doing things for myself so I could keep her happy, and that kept the 'voices' at bay for a while. But in the past two months that she's been in college they have come back in full force and so I have been depressed. And yesterday she told she wanted to leave. I guess she finally realized I wasn't giving her what she needed emotionally, etc...
Something weird happened. Instead of falling deeper into depression and feeling sorry for myself, for the first time in my life I realized I have to love myself in order to be able to accomplish things. I got tired of ME, so I couldn't blame her. I told the other me to go away and never come back. I told her she could leave if she wanted, and that I wouldn't hold anything against her. Although it hurts, life happens and seeing her suffer all the same (despite cheating on me and going away with somebody else) helped me realize we all make mistakes. My mistake was marrying her, despite what I felt for her. I didn't see her as a wife but as someone that could fix my own problems.
All of this happened yesterday... today I have accomplished more than what I've done in years. It's empowering to know despite the horrible things that happen in life, there's still some kind of control that you can exert over some of the things in your life.
I guess I don't have much else to say. Hopefully some of the people here can experience something similar. And believe me, it's not easy, but it can happen.