James,
I have read Mary Chestnut's diary in the past. Interesting reading. I think that Mary might have suffered from depression before the war and it was exascerbated by the coming of the hostilites and he worry about her husband. The south had an aristocratic society in those days and in the Charleston area she and her husband would have been very involved. He had a good woman for a wife in my opinion. I think Mary Lincoln had the same problem.
Frank