Why is there a time of physical separation between husband and wife every month – a law found in this week’s Torah portion? (Leviticus 15) To be sure, a mandate ought be observed no matter – but is there a rationale?
Perhaps the separation points to a difference between Jewish and fundamentalist Christian approaches to sexuality. In Christianity the basic purpose of sex is procreation. In Judaism, as important as pru u’rvu (procreation) may be, onah, that is, sexual pleasure as an expression of deep love, is even more important. Note the words of Ramban: “Speak words which arouse her to passion, union, love, desire and eros” (Epistle of Holiness). Of course, such words and actions should be reciprocated by wife to husband.
It may be suggested that a time frame of separation is mandated to heighten the physical encounter. A kind of pause that refreshes, allowing for the love encounter between husband and wife to be more wholesome, more beautiful.
A second approach comes to mind. Martin Buber speaks of an I/it encounter, where the “I” relates to the other as a thing, an object to be manipulated and used to satisfy the “I.” This in contrast to the I/thou encounter where the other is a persona, a subject to be considered and loved.
Hundreds of years before Buber, Rambam in his commentary to the Mishnah (Avot 1:16) wrote about love between husband and wife as empathetic friendship, a camaraderie involving a caring responsiveness, a sharing of innermost feelings… a relationship of emotional rapport rooted in faith and confidence.
Here again, a time frame of separation may be mandated to make sure that spouses can relate in ways other than physical, and then transfer those feelings to the sexual act itself. The separation is intended to teach that I/thou is intrinsic to the sexual encounter.
One last approach: In many ways love is not only holding on but letting go. To be sure, love involves embracing the other, but in the same breath it allows the other to realize his or her potential. This is the great challenge of harmonization. How can I be one with you while letting you be who you are? On the other hand, how can you be who you are without our becoming distant and alienated from each other?
This could be the meaning of ezer k’negdo (Genesis 2:18) which Rav Yosef Dov Soloveitchik understands as Adam’s “discovery of a companion who even though as unique and singular as he, will master the art of communicating and with him form a community” (Lonely Man of Faith, p.26). In Milton Steinberg’s words, real love is “to hold with open arms.”
Therefore a time frame of separation is mandated to foster individuality even as the coming together fosters commonalty. Each is stressed in the hope that they spill over and become part of the other and forge a balance.
These rationales do not explain why the separation takes place at the time of niddus (menstruation) or why immersion in a mikveh is crucial for purification, but they may offer some understanding of why the Torah sees the separation as a conduit to enhancing love between husband and wife.