Michigan 1987

In Michigan 1981, a wife's house was broken into by her husband. He raped her at knife point for an hour. In 1982, he was convicted of rape and sentenced to 27 years in prison. In 1987, the Appellate Court overturned the conviction 3-0 saying that in Michigan, a wife could not have been ''raped'' by her husband because it was not a crime for a man to sexually assault his wife unless they were living apart and one had filed for divorce.  She did not file for divorce in 1981, because she had not been a Michigan resident for the mandatory six months.

In 1975, South Dakota was the first state to outlaw marital rape when the couple was living together. By 1987, 25 states had outlawed the practice.[NYT]