taken from a dear abby letter from 1964:

"DEAR ABBY: Why will a married man pick up a tramp and treat her like a lady, then turn around and treat his wife (who is a lady) like a tramp? -- MINNIE

"DEAR MINNIE: A man picks up a tramp because he wants a female companion who is no better than he is. In her company, he doesn't feel inferior. He rewards her by treating her like a lady.

"He treats his wife (who is a lady) like a tramp because he feels that by degrading her, he will bring her down to his level. This makes him feel guilty, so to get even with his wife for making him feel guilty, he keeps right on punishing her."