New to battling depression

I've always been pretty stable when it came to my emotions and mental health. Recently, my wife hit her midlife crisis and has changed dramatically. I won't go into the details here, I put those in the relationship thread, but it has sent me spiraling downward into depression. Something that I've ever had to deal with before. I guess I would say it's more manic/depressant as there are many very good days. But everytime I have a down day, it gets worse and worse. I'm just hurting so much and carrying so much weight on my shoulders and I don't know where to turn. I did try a therapist, but she was hoorendous and really turned me off to the idea of therapy. I really don't know how much lower I can go. What can I do to make this pain go away?