Love Must Be Tough by Dobson is a good book to read, but you cannot utilize a lot of the techniques w/someone in mlc. This book is for those who have spouses that are having affairs that are normal, rational people. Your spouse is not normal in many respects...when depression of this magnitude hits, Dobson's book will only make him/her choose the easiest solution to the problem...divorce.
You cannot get into his head. It's a mess. If he can't get himself together, how do you think you can figure him out? Analyzing and over analyzing will get you no where but nuts. Step back, allow him to swing in the wind. You will need to find a way to keep the focus on you. It's very important that you take care of yourself during this time. It's a long process and it will stress your immune system to the max if you aren't careful. Take up some hobbies, clean your house top to bottom, join a club, but whatever you do, do it for you, not him.
My advice....read, read and read. Start reading the current threads and posting. By staying here on your thread, people will not post as they would if you became a "family" member of the group. The more your interact w/others, the more people are apt to post and come visit w/you here.
