Newt Gingrich has filed for divorce from his wife, Marianne, after 18 years of marriage.
Papers filed Thursday in the Superior Court of Cobb County, Ga., said the couple -- married Aug. 8, 1981 -- have been separated since May 10.
"The cause of the ... separation was the fact that the marriage is irretrievably broken," the papers said. They added that Gingrich and his wife were attempting to reach a settlement "resolving all matters and controversies between them."
Mrs. Gingrich could not be reached for comment.
The former House Speaker reserved the right to "set forth additional grounds for divorce" if the parties could not reach an agreement.
Gingrich, architect of the Republican revolution in the House, served as speaker from 1995 until the end of last year, when he gave up his seat in Congress. The marriage was his second.