The Talmud in Tractate Niddah - which deals with the laws of ritual purity pertaining mainly to menstruant women and sexual activity in general - quotes this interesting statement (page 17a):
"Rav Chisda says: It is forbidden for a man to have sexual relations during the day, as it is written 'and you shall love your neighbor as yourself'. How does this verse imply this law? Abayye says: lest he see in her [his wife] an unseemly thing, and she become unattractive to him."
The idea seems to be that in the daytime, as opposed to in the dark of night, one sees things more clearly, and therefore, during the act of sex, one runs the risk of seeing something unattractive, unaesthetic, and being turned off. This risk is lessened in the dark, so making love in the dark (it would seem that Rav Chisda is playing with the word "love" here) would seem to be an expression of loving your neighbor - in this case your wife - as yourself (not sure about that, but we will come back to it) by giving her a break, being nice to her, taking the pressure off of her to always look perfect, and love her even if she has an unseen blemish or two.
Immediately after this statement, the Talmud continues:
"Rav Huna says: The people of Israel are holy, and do not have marital relations during the day. Rava says: If it was in a darkened house it is permitted, and a scholar may make it dark with his cloak and have relations [presumably scholars in particular are to be trusted to get this tricky little maneuver right].''
This rule, that one should have sex only at night, or in the dark, is stated a few more times in the Talmud, and is in fact codified by Maimonides and others. In this formulation, the reason would seem to be that it is brazen and immodest to have sex in the light of day - not holy - and good Jewish men and women are meant to be holy and make love modestly. Rav Chisda's 'love they neighbor as yourself' reason for making love in the dark seems aimed, if not in the opposite direction, then at least in a different one, that of enhancing and encouraging a positive erotic connection between husband and wife; he does not seem to be concerned with modesty. Rather, he seems to focus on the aesthetic aspect of intimate relations: merely seeing something unseemly in one's partner would, it seems, render her (and perhaps him, as well, though that is not the point of view from which the men of the Talmud were operating) undesirable, so, for a happy love life, keep the lights off.
These two statements seem, at first glance, to be somewhat contradictory; the one a kind of marital advice to couples type of thing, the other an expression of a desire to minimize excessive passion in the sex act. Interestingly, however, the Talmud does not in any way see these two positions as adversarial, it just quotes one after the other, as if they go together. Perhaps this is the case. Perhaps the two statements are coming from the same place, and basically expressing the same thing - a desire to improve the quality of intimacy in a relationship. I will try and explain how.
I am sure that all of you have noticed (no matter how hard you have tried not to) that pornography has entered the aesthetic mainstream. The way that women are represented in music videos, Hollywood, fashion, even works of "serious" "art" (have I used enough quotation marks to make my point, Jeff Koons, et al.?) more and more takes its inspiration from pornography, where woman is objectified by the male gaze as a personification of a posed, sleazy, voyeuristic, often fetishized sexuality, divorced from love or even relationship, always available, and, crucially, always on display. In this dynamic, the woman is an object enjoyed visually by the male watcher/lover, who functions primarily as a voyeur, of both his partner and of the very act of sex. Sex, in this aesthetic, is something that is first and foremost watched, rather than engaged in.
(The above has always been true, to some degree, in western art; I am claiming a worsening of the situation, a coarsening of this essentially male, voyeuristic way of representing women and sexuality).
The Talmud, here, in the laws of modesty during intimacy, is polemicizing against this approach, and argues for modesty as a positive and crucial element in an intimate relationship - not only for the sake of modesty, but, more importantly, for the sake of relationship. A sexuality that reveals all, and puts everything (typically everything the woman has) on display, is not only immodest. It also sets up a kind of sexual aesthetic that a woman can almost never live up to, for, in an interaction of this type, the lover/voyeur will inevitably find something unpleasing in the object of his desire, something not quite good-looking enough, and move on. The modesty prescribed in the Talmud calls for a sexuality which is based not primarily on the visual and aesthetic pleasure given by an object of desire to the beholder/enjoyer of that object, but, rather, on a commitment to find something deeper, something beyond an inevitably fleeting aesthetic experience. (The connection between the above and the prohibition against making a graven image, which is essentially about making a divine, rather than sexual, figure, is worth thinking about.)
Perhaps Rav Chisda, with his use of the 'love your neighbor' verse, is asking us to love our closest neighbor - our spouse - the way we love ourselves, which is a love based on who I really am, not on how I look. All of us realize (well, should realize, anyway) that, even when we see a pimple in the mirror, put on a few extra pounds, or notice a receding hairline, we are still us, and we, hopefully, still feel good about ourselves, still know and like who we really are. Rav Chisda in the Talmud reads the 'love your neighbor as yourself' verse as asking us to use modesty to help us achieve and maintain that same kind of love, a love of knowing and experiencing, with our partner, rather than just seeing her - or him - as an object to be enjoyed.
Shabbat Shalom,
Shimon