In her chapter on inseparable romantic friends, Donoghue says that "opposites attract ... is one of our culture's most beloved truisms" (60).
The fact is, in Renaissance literature, love was very often thought to be based not on contrast but on similarity; the classical model was the romantic bond between two men. Like calls to like; birds of a feather flock together. There is an intriguing exchange in Honore D'Urfe's (1607-1627), when a jealous man called Hylas asks sneeringly if "Alexis" (a man disguised as a priestess) finds shepherdesses more appealing than shepherds, and "she" answers proudly, "Have no doubt about it, and blame no one but nature, who wants everyone to love his own kind." When Leonard Willan dramatizes D'Urfe's saga as Astraea (1651), he included a debate between a woman and a man, to be judged by their mutual object of desire, Diana. Phillis argues that same-sex passion is strongest because love grows from "Equality and Sympathy"; Sylvander counters that mating requires difference.What this shows, of course, is that both conceptions of love co-existed then, as they do now. (With good reason: both conceptions play a role in human loving.) It brought to mind some arguments I've seen about the value of same-sex erotic relationships, apart from the question of marriage. Some religious bigots have been arguing -- without any real basis for their arguments, of course -- that two men or two women can't form a couple as rich and rewarding as a mixed-sex couple, partly because men and women are opposites. Or because they're an animalistic fact of nature. Orson Scott Card also argued for the superiority of heterosexual marriage because it was unnatural, because it's “very, very hard -- to combine the lives of a male and female, with all their physical and personality differences, into a stable relationship that persists across time.”
You plead th'advantage of your Sexe, as bent
To love sembable were natures Intent;
In Beasts see where her motives simple be,
Their prevservations shall t'each contrarie [60-61].
But even within the Christian tradition these are shaky positions. Neither Jesus nor Paul thought much of heterosexuality, not even marriage. True, Paul used marriage as a metaphor for the relationship between Christ the Bridegroom and the Church the Bride -- but not between Christ and the individual believer, who he thought would do better to remain single if possible. The individual believer was the slave of Christ, not his bride. And I don't see oppositeness as the guiding conception of the sexes in the Genesis creation myths. Whether you go with Genesis 1, which has us created, male and female in Yahweh's image; or Genesis 2, where Eve was created from Adam's rib to be his helper, you won't find a meeting of opposites where men and women are concerned. The conception of sex/gender in the Hebrew Bible, at least, is more like the "one sex" model described by Thomas Laqueur in Making Sex: Body and Gender from the Greeks to Freud (Harvard, 1990).
Donoghue offers the story of Ruth and Naomi as an example of inseparable female friends. (The story of David and Jonathan is similar: "the soul of Jonathan was knit to the soul of David, and Jonathan loved him as himself" [1 Samuel 18:1-4].) Whether either relationship had erotic elements, it's significant that Ruth's famous words to Naomi have often been used in heterosexual weddings. If same-sex couples are so different from mixed-sex couples, and indeed inferior to them, why do heterosexuals keep using same-sex couples as their models?