Havelock Ellis,
Studies in the Psychology of Sex…
“ It is not monogamy that is the main thing, but the kind of lives that people lead in monogamy. The mere acceptance of a monogamic rule carries us but a little way. That is a fact which cannot fail to impress itself on those who approach the questions of sex from the psychological side.If monogamy is thus firmly based it is unreasonable to fear, or to hope for, any radical modification in the institution of marriage, regarded, not under its temporary religious and legal aspects but as an order which appeared on the earth even earlier than man. ”
