How did the black veil become associated with married women?
Below is a photo that I took of the widow's veil at the Louisiana State Museum on Jackson Square in New Orleans. You can see how it is meant to cover the face and undoubtably the tears of the woman who wore it.
The widows veil of mourning.
A widow in mourning was required to wear black for about one to two years after the death of her husband. So say for example the woman was widowed and she began the morning process of wearing black. If during that year another family member died, she would begin the full morning all over again from the very beginning.