Between 1992 and 1994, South Dakota was one of four states (the others being New York, Missouri, and Mississippi) to experience a rise in divorce rates.
South Dakota has a low rate of divorce: 3.1% per 1,000 of the total population which is below the average divorce rate in most other states.
Not surprisingly, one of the more commonly cited reasons for divorce is adultery.
South Dakota defines adultery as voluntary sexual intercourse of a married person with one of the opposite sex to whom he or she is not married. – South Dakota Laws - Volume 9A - Title 25 - Chapters: 25-4-2, 25-4-17, 25-4-18