Most North Dakota residents would agree that extra-marital affairs should be avoided whenever possible, and they would also agree that they are quite common. What they might not know, however, is that under the technicality of the law, an extra-marital affair could also be considered illegal in some states.
In 2005, the wife of a 29-year-old airman contacted police to inform that her spouse was involved in an affair with a 16-year-old girl. In this case, the issue was obviously one of criminal importance because the girl was under the age of 18. However, there have also been prosecutions relating to extra-marital affairs between two consenting adults. For example, in 1991, a New York woman accused her husband of engaging in sexual relations with another woman. The 1991 case was particularly noteworthy because it was the first such criminal matter concerning a cheating spouse and two consenting adults in the state since 1940.
Also, in 1989 in Wisconsin, a man accused his wife of committing the crime of adultery during a contentious child custody battle -- and it was the first such case in the state since 1888. In the 1989 case, the accused woman's husband confessed to committing adultery, too, but prosecutors could not move forward with the criminal allegations because the affair happened while the man was across state lines. The woman could have been sentenced to a two-year jail term had she been convicted, in addition to a $10,000 fine. However, the woman agreed to participate in a community service program in addition to parental counseling and prosecutors dismissed her case.
The fact is, even though adultery is still illegal under the technicality of the law in many states, it is highly unlikely that such criminal charges would ever stick. However, if the alleged adultery was committed in relation to a sex crime, sexual assault or some other criminal event, those charges could stick and they could ultimately affect one's North Dakota child custody proceedings.
Source: Salon, "Your affair might be illegal: Inside the complicated world — and 21 states — where adultery remains against the law," Deborah L. Rhode, April 02, 2016