Neither can he be thought guilty of a greater Crime [than manslaughter], who finding a Man in Bed with his Wife, or being actually struck by him, or pulled by the Nose, or filliped upon the Forehead, immediately kills him.”
It used to be in the United States, that if you came home and found your wife in bed with the postman, it was perfectly okay to get your shotgun and blow the heads off both of them.”
Professors of criminal law like to impress their students with the “unwritten law of adulterous provocation.” It is seldom part of the curriculum; usually, it seems to present itself off-the-cuff, a professorial ploy to keep lectures interesting, a juridical curiosity that the students can regale friends and family with over dinner. In some classrooms, the unwritten law is limited to the southern United States or to Texas. In my case, at a southern Ontario law school, the entire U.S.A. (with the possible exception of Alaska and Hawaii) was implicated.
My teacher probably had heard the same story in a slightly different language from his own professor of introductory criminal law. Rather than gustily losing their heads, perhaps the lovers were “filled full of lead,” or the husband treated his wife to a summary shotgun divorce.