Depression can do a number on relationships when one party isn't supportive can't it? I guess my first question: is he supportive now? Would it be helpful for you both to go to therapy to work through this? Leaving a marriage is a big decision so give yourself time and don't make sudden decisions. Do you think with some time and with the help of a therapist you could process your feelings? In my situation I was married for 19 years. He doesn't believe in mental illness and was not only not supportive but actively disdainful. Even though we had a child I decided (it was a tough decision) to divorce. I started getting better once I asked him to leave. The relationship was making my depression much worse. I think you should concentrate on healing your depression but that's a catch 22 if he is exacerbating it. It's a tough situation.

I wish you wisdom and peace in coming to a decision.