Laws criminalizing adultery are on the books in a handful of other states but are rarely enforced. In most cases, they were put on the books at a time when adultery was among the only ways to obtain a divorce, according to Carol Faulkner, a history professor at Syracuse University who studies 19th-century America, women and social movements and authored the 2019 book, “Unfaithful: Love, Adultery, and Marriage Reform in Nineteenth-Century America.”

After the American Revolution, New York State continued to be much more aligned with English laws, where it remained hard to get a divorce, Faulkner said. In the 19th century, only New York State and South Carolina had restrictions on divorce.