Rav Moshe Cordovero teaches that the proper conduct within marriage, including times of separation, should model Divine attributes of compassion and holiness, transforming the physical relationship into a vehicle of spiritual union.
לעשות שהשכינה תדבק בו על ידי ההתנהגות עם אשתו: עוֹד זְהִירוּת הַרְבֵּה צָרִיךְ לִקַּח הָאָדָם לְעַצְמוֹ לַעֲשׂוֹת שֶׁתִּהְיֶה שְׁכִינָה דְּבֵקָה עִמּוֹ וְלֹא תִפָּרֵד מִמֶּנּוּ, וְהִנֵּה הָאָדָם בְּעוֹד שֶׁלֹּא נָשָׂא אִשָּׁה פְּשִׁיטָא שֶּׁאֵין עִמּוֹ שְׁכִינָה כְּלָל כִּי עִקַּר שְׁכִינָה לָאָדָם מִצַּד הַנְּקֵבָה, וְהָאָדָם עוֹמֵד בֵּין שְׁתֵּי הַנְּקֵבוֹת, נְקֵבָה תַּחְתּוֹנָה גַּשְׁמִית שֶׁהִיא נוֹטֶלֶת מִמֶּנּוּ שְׁאֵר כְּסוּת וְעוֹנָה, וְהַשְּׁכִינָה הָעוֹמֶדֶת עָלָיו לְבָרְכוֹ בְּכֻלָּם שֶׁיִּתֵּן וְיַחְזֹר וְיִתֵּן לְאֵשֶׁת בְּרִיתוֹ כְּעִנְיַן הַתִּפְאֶרֶת שֶׁהוּא עוֹמֵד בֵּין שְׁתֵּי הַנְּקֵבוֹת, אִימָּא עִילָּאָה לְהַשְׁפִּיעַ לוֹ כָּל הַצֹּרֶךְ, וְאִימָּא תַּתָּאָה לְקַבֵּל מִמֶּנּוּ שְׁאֵר כְּסוּת וְעוֹנָה, חֶסֶד דִּין רַחֲמִים כַּנּוֹדָע.וְלֹא תָבֹא אֵלָיו שְׁכִינָה אִם לֹא יְדֻמֶּה אֶל מְצִיאוּת הָעֶלְיוֹן. וְהִנֵּה לִפְעָמִים הָאָדָם פּוֹרֵשׁ מֵאִשְׁתּוֹ לְאַחַת מִשְּׁלֹשָׁה סִבּוֹת: הָא' - לִהְיוֹתָהּ נִדָּה. הַב' - שֶׁהוּא עוֹסֵק בַּתּוֹרָה וּבוֹדֵל מִמֶּנָּהּ כָּל יְמֵי הַחֹל. הַג' - שֶׁהוּא הוֹלֵךְ בַּדֶּרֶךְ וְשׁוֹמֵר עַצְמוֹ מִן הַחֵטְא. וּבִזְמַנִּים אֵלּוּ הַשְּׁכִינָה דְּבֵקָה וּקְשׁוּרָה עִמּוֹ וְאֵינָהּ מַנַּחַת אוֹתוֹ, כְּדֵי שֶׁלֹּא יִהְיֶה נֶעֱזָב וְנִפְרָד, אֶלָּא לְעוֹלָם אָדָם שָׁלֵם זָכָר וּנְקֵבָה, וַהֲרֵי שְׁכִינָה מִזְדַּוֶּגֶת לוֹ, צָרִיךְ אָדָם לִזָּהֵר שֶׁלֹּא תִפָּרֵד שְׁכִינָה מִמֶּנּוּ בִּהְיוֹתוֹ יוֹצֵא לַדֶּרֶךְ, וְיִהְיֶה זָרִיז וְנִשְׂכַּר לְהִתְפַּלֵּל תְּפִלַּת הַדֶּרֶךְ וְלֶאֱחֹז בַּתּוֹרָה, שֶׁבְּסִבָּה זוֹ שְׁכִינָה שֶׁהִיא שְׁמִירַת הַדֶּרֶךְ, עוֹמֶדֶת לוֹ תָמִיד בִּהְיוֹתוֹ זָהִיר מִן הַחֵטְא וְעוֹסֵק בַּתּוֹרָה. וְכֵן בִּהְיוֹת אִשְׁתּוֹ נִדָּה שְׁכִינָה עוֹמֶדֶת לוֹ כְּשֶׁשּׁוֹמֵר הַנִּדָּה כָּרָאוּי. אַחַר כָּךְ בְּלֵיל טָהֳרָתָהּ אוֹ בְּלֵיל שַׁבָּת אוֹ בְּבֹאוֹ מִן הַדֶּרֶךְ, כָּל אֶחָד מֵהֶן זְמַן בְּעִילַת מִצְוָה הוּא. וּשְׁכִינָה תָּמִיד נִפְתַּחַת לְמַעְלָה לְקַבֵּל נְשָׁמוֹת קְדוֹשׁוֹת, גַּם אִשְׁתּוֹ רָאוּי לִפְקֹד אֹתָהּ וּבָזֶה שְׁכִינָה תָמִיד עִמּוֹ, כֵּן פֵּרֵשׁ בַּזֹּהַר בְּפָרָשַׁת בְּרֵאשִׁית (דַּף מ"ט.). הַפְּקִידָה לְאִשְׁתּוֹ צָרִיךְ שֶׁתִּהְיֶה דַּוְקָא בִּזְמַן שֶׁהַשְּׁכִינָה בִּמְקוֹמָהּ, דְּהַיְנוּ כְּשֶׁהִיא בֵּין שְׁתֵּי זְרוֹעוֹת. אָמְנָם בִּזְמַן צָרַת הַצִּבּוּר שֶּׁאֵין הַשְּׁכִינָה בֵּין שְׁתֵּי זְרוֹעוֹת, אָסוּר. וְכֵן פֵּרְשׁוּ בַּתִּקּוּנִים פָּרָשַׁת בְּרֵאשִׁית (תִּקּוּן ס"ט).
To make it that the Divine Presence clings to him by his behavior with his wife: There is also much care that a man must take for himself [in this] to make it that the Divine Presence be clinging to him and not separate from him. And behold, it is obvious that when a man has not yet married a woman, the Divine Presence is not with him at all; as the essence of the Divine Presence for a man is from the side of the female. And a man stands between the two females - the lower physical female, who takes 'flesh, covering and time' from him; and the Divine Presence that stands above him, to bless him with all of them, that he give and give again to the wife of his covenant. [This is] like the matter of Splendor that stands between two Females - the Higher Mother (Understanding) that flows all that is needed to Him; and the Lower Mother (Kingship), [that] receives from Him, 'flesh, covering and time,' which are Kindness, judgement (Severity) and mercy (Splendor), as is known. And the Divine Presence will not come to him if he does not resemble the Highest Existence. Behold, sometimes a man separates from his wife for one of three reasons: The first - in her being a menstruant. The second - in his being occupied with Torah and separating from her all of the weekdays. The third - in his going on the way and guarding himself from sin. And at these times, the Divine Presence is clinging and bound to him and It does not leave him, so that he not be abandoned and separated. Rather the man is always complete, male and female. And behold [since] the Divine Presence is coupled with him when he goes out on the way, a man must be careful that It not separate from him. And he [should] be alacritous and rewarded to pray the prayer of the way and to hold on to Torah. As from this reason, the Divine Presence - which is Protection of the way - always stands for him; in that he is being careful from sin and occupied with Torah. And so [too,] when his wife is a menstruant, the Divine Present stands upon him - when he observes [the laws of] the menstruant as is fitting. Afterwards on the night of her purity, on the Shabbat night or on his coming back from the way - each one of them is a time of commanded intercourse. And the Divine Presence above opens to accept holy souls; so is his wife fitting to visit her. And with this, the Divine Presence is always with him. So is it explained in the Zohar in Parshat Bereishit (p. 49a). The visiting of his wife must be specifically at the time that the Divine Presence is between the two Forearms (Kindness and Severity). However at a time that the Divine Presence is not between the two Forearms, it is forbidden. And so is it explained in the Tikkunim, Parshat Bereishit (Tikkun 69).