There is some confusion about Marital status I have come across.
So, I will generally define them here.

Single - Never Married
Married - A Union sanctioned by State and Church

Estranged - Married, but not sharing a common residence
    (a divorce may or may not be pending)
Seperated - Married, but not legally responsible for actions of spouse
    (a court action has been completed)
Divorced - No longer Married
    (a court action has been completed)

Widow(er) - Marriage partner is deceased

Other - a situation that may involve another person (it's complicated)