Not a secret, that in the childhood to us the certain role models directly connected to sexual distinctions pawn: the girl always princess, and the boy - knight. On a white horse, naturally. Then people mature also everyone understand, but for the children's rank usually apply still (to apply substantiations to the requirements apply, and, frequently do not create). And search, since childhood, the happiness which should be unique and unique (if to trust fairy tales).
About this speaks both a myth about the husband and the wife, as a unit, or, accordingly, two half.