Two quotes:

"This poor ersatz Martian is saying that sex is a way to be happy. Sex should be a means of happiness. Ben, the worst thing about sex is that we use it to hurt each other. It ought never to hurt; it should bring happiness, or at least pleasure.
"The code says, 'Thou shalt not covet thy neighbor's wife.' The result? Reluctant chastity, bitterness, blows and sometimes murder, broken homes and twisted children — and furtive little passes degrading to woman and man. Is this Commandment ever obeyed? If a man swore on his own Bible that he refrained from coveting his neighbor's wife because the code forbade it, I would suspect either self-deception or subnormal sexuality. Any man virile enough to sire a child has coveted many women, whether he acts or not.


Jealousy is a disease, love is a healthy condition. The immature mind often mistakes one for the other, or assumes that the greater the love, the greater the jealousy — in fact, they are almost incompatible; one emotion hardly leaves room for the other.

from: Stranger in a strange land

Everybody should read this book ...