Meli, It sounds to me like you are doing the absolute best you can under these trying circumstances. Your daily affirmation should include the words,
"This is not my fault. I do not deserve to be treated like this."
Take a look at robx's post on standing up for yourself. It is a very inspiring read about how he changed the dynamic in his M when he decided to stop being a doormat and start loving and caring for himself.
As far as your H goes, is he still taking his medication? I am on Celexa myself for depression, and it is doing wonders for me and my mood so I am curious if your H was seeing any beneficial results from it. You do have to take it for a while to start getting the effects, though. Is he currently under the care of a physician or a mental-health specialist?
Regardless of where he is in his life and his condition, loving detachment will help you the most. It can be a tricky thing to pull off, both because you do have feelings for your H and no one wants to see their Sp hurting, and because you do need to detach from them to improve yourself. Find a focus that can keep your mind from flitting back into depressing thoughts. Your kids are an excellent focus, and they probably do need you right now more than ever.
Here are two classic links to a laundry list of things that you can do as a LBS. The first is from Coach's Film guide, and the second is from Bowtech's archived thread. Both are long reads, but the gems are sprinkled liberally throughout.
