“One fool at least in every married couple.”

http://www.eluniversal.com.mx/notas/551253.html

The Roycraft Dictionary and Book of Epigrams (1923)
Source: The Roycroft Dictionary Concocted by Ali Baba and the Bunch on Rainy Days

Wonder Boys (1995)

1940s–present, A Mencken Chrestomathy (1949)

Doris, Chapter 12, p. 162
Source: 2000s, At First Sight (2005)
Context: ... What's going on with you two, all this stress you're both under... that's called life. And life has a tendency to throw curveballs when you least expect them. Every couple has ups and downs, every couple argues, and that's the thing--you're a couple, and couples can't function without trust. You have to trust him, and he's got to trust you.

The Complete Neurotic's Notebook (1981), Marriage

Journal for Saturday, 27th November 1813; Quoted in Letters and Journals of Lord Byron by Thomas Moore (1830), Vol III, Chap. XVII, p. 208 http://books.google.com/books?id=nloLAAAAIAAJ&pg=PA208

Source: Rant

The allegation that Catharine MacKinnon equated sex with rape, or suggested that all sex is hostile, seems to have been first made in the October 1986 issue of Playboy. Catharine MacKinnon has denied ever saying anything of the kind. http://www.snopes.com/quotes/mackinno.htm
Instead MacKinnon asserts that rape and intercourse are "difficult to distinguish" (1983), and that "the major distinction between intercourse (normal) and rape (abnormal) is that the normal happens so often that one cannot get anyone to see anything wrong with it" (1989).
Misattributed