I am so sorry. My husband decided he wanted out after 11 years this past Valentine's, and it is horrible, horrible, horrible. But we didn't have a child, so I can only imagine your pain over that part of the possible future.
It seems like you really need a mood stabilizer. I tend to spend most of my time being depressed, and my doctor just added Abilify to my mix, and it has made a world of difference for me. Perhaps it might help you as well? Before, I would want to do things, but just couldn't seem to get myself to do them; I slept too much; or I would get so bad I wouldn't even want to do my favorite things like watch movies or paint. The very next day I had a difference, felt motivation and completed tasks, and began to feel good, a good I hadn't felt in years.
Since you are being honest about your feelings, I wonder, are there reasons why YOU might be better without your husband? It was very hard to come to terms with, but I have to admit in the end, that my relationship with my husband not only made many of my issues worst, but was the origin of alot of them. Perhaps you too might be a butterfly just biding time in a cocoon, waiting to be let free to fly and have a happy, fulfilling life.