אבן העזר ס״וEven HaEzer 66

Se’if 1א׳

אָסוּר לְהִתְיַחֵד עִם הַכַּלָּה קֹדֶם שֶׁיִּכְתֹּב לָהּ כְּתֻבָּה; וְיֵשׁ מְקִלִּין וּמַתִּירִין לְהִתְיַחֵד בְּלֹא כְּתֻבָּה, וּבִלְבַד שֶׁלֹּא יִבְעֹל (הָרַ"ן רֵישׁ כְּתֻבּוֹת); וְהַבַּעַל נוֹתֵן שְׂכַר הַסוֹפֵר. וַאֲפִלּוּ אִם יִרְצֶה לְיַחֵד לָהּ כְּתֻבָּתָהּ בְּמָעוֹת, אוֹ בִּשְׁאָר מִטַּלְטְלִין, אֵין שׁוֹמְעִין לוֹ, אֶלָּא צָרִיךְ שֶׁיִּכְתֹּב לָהּ שְׁטָר עַל עַצְמוֹ בִּדְמֵי הַכְּתֻבָּה וְיִהְיוּ כָּל נְכָסָיו מְשֻׁעְבָּדִים לָהּ, אוֹ שֶׁיָּעִידוּ עָלָיו עֵדִים וְיִקְנוּ מִיָּדוֹ שֶּׁהוּא חַיָּב לָהּ, מָנֶה אוֹ מָאתַיִם. הַגָּה: וְיֵשׁ אוֹמְרִים דְּאֵין לִסְמֹךְ אָעֵדִים רַק בִּשְׁעַת הַדְּחָק, וּמִיָּד שֶׁיֵּשׁ לוֹ פְּנַאי לִכְתֹּב, צָרִיךְ לִכְתֹּב, כָּל שֶׁכֵּן שֶׁאֵין לִסְמֹךְ עֲלָיְהוּ לְכַתְּחִלָּה (כֵּן מַשְׁמַע מִלְּשׁוֹן הַטּוּר, וְכֵן כָּתְבוּ מַהֲרִי"ק שֹׁרֶשׁ ס"ד וּמָרְדְּכַי רֵישׁ כְּתֻבּוֹת), וְכֵן רָאוּי לְהוֹרוֹת. הֶעֱמִיד לָהּ עָרֵב קַבְּלָן בְּעַד כְּתֻבָּתָה, וְהִתְנָה שֶׁהוּא יְהֵא פָּטוּר מִמֶּנָּה, אָסוּר, עַד שֶׁיְּהֵא שִׁעְבּוּדָהּ עָלָיו, שֶׁלֹּא תְּהֵא קַלָּה בְּעֵינָיו לְהוֹצִיאָהּ (בֵּית יוֹסֵף בְּשֵׁם הָרַשְׁבָּ"א בִּתְשׁוּבָה ח"ב סי' נ"ח). וְעַיֵּן בְּחשֶׁן הַמִּשְׁפָּט סִימָן ס' אִם יוּכַל לְשַׁעְבֵּד עַצְמוֹ בִּכְתֻבָּתָהּ בִּנְכָסִים שֶׁלֹּא בָּאוּ לָעוֹלָם. וְאֵין לָעֵדִים לַחְתֹּם הַכְּתֻבָּה אֶלָּא לְאַחַר שֶׁקִּבֵּל הֶחָתָן קִנְיָן לִפְנֵיהֶם (דִּבְרֵי הָרַב). וְיֵשׁ מְקוֹמוֹת שֶׁמְּקִלִּין בָּזֶה (מָרְדְּכַי פ"ב דְּגִטִּין); וְכֵן שֶׁיֵּשׁ עֵדִים חוֹתְמִים עַל הַכְּתֻבּוֹת שֶׁקָּרְאוּ תַּחַת הַחֻפָּה, אַף עַל פִּי שֶׁהֵם לֹא שָׁמְעוּ הַקְּרִיאָה; אַף עַל פִּי דְּלָא שַׁפִּיר עָבְדֵי, אֵין לְשַׁנּוֹת מִנְהָגָן, שֶׁלֹּא לְהוֹצִיא לַעַז עַל כְּתֻבּוֹת הָרִאשׁוֹנוֹת (אוֹר זָרוּעַ):

It is forbidden [for the groom] to seclude himself with the bride before he has written her the ketubah, Rem"a: There are some who are lenient and allow [being alone together] without a ketubah provided that they do not have sexual relations. (Ran, beginning of Tractate Ketubot). and the groom pays the scribe's fee [for writing the ketubah]. Even if he wants to set aside her ketubah with money [i.e. the monetary payment that is stipulated in the ketubah], or with other goods [which have the value of the ketubah], we do not listen to him. Rather he needs to write a contract that obligates himself to pay her the monetary value of the ketubah, all his assets have a lien on them, or witness can witness and and they effect transfer directly from [the groom] that he is obligated [to pay] her 100 or 200 [the value stipulated by the ketubah]. Rem"a: Some say that we only rely on witnesses in exigent circumstances. As soon as he is free to write [a ketubah], he is required to write one, all the more so we do not rely on [witnesses] preferably (Inferred from the language of the Tur, and what was written by the Maharik Shoresh 64, and the Mordechai at the beginning of Tractate Ketubot) And such is proper to disseminate. If he appoints a ketubah delivery guarantor for her, and he makes the condition that he [himself] should be exempt from [paying] her, this is forbidden, until he makes it a lien on himself, so that it should not be an easy thing for him to divorce her (Bet Yosef in the name of the Teshuvot HaRashba 2:58) And see Choshen Mishpat 60 if he can make a lien on himself for the ketubah from something that has yet to come into existence. And the witnesses should only sign the ketubah after the groom effects the transfer before them (Divrei HaRav). Some places are lenient about this (Mordechai, Tractate Gittin chapter 2). And so there should be signing witnesses for the ketubah read under the wedding canopy, even if they didn't hear it read; even though they didn't act well [by not hearing it read], we do not change the custom, as we don't cast aspersions on previous ketubahs (Or Zarua).

Se’if 2ב׳

אִם אֵינוֹ יָכוֹל לִכְתֹּב לָהּ כְּתֻבָּה, כְּגוֹן בְּשַׁבָּת, אוֹ שֶׁשָּׁכַח לְכָתְבָהּ, יָכוֹל לִתֵּן לָהּ מִטַּלְטְלִין כְּנֶגֶד כְּתֻבָּתָהּ, וִיקַבֵּל עָלָיו אַחֲרָיוּת אִם יֹאבְדוּ אוֹ יוּזְלוּ, וְאָז מֻתָּר לִבְעֹל עַד שֶׁיִּהְיֶה לוֹ פְּנַאי לִכְתֹּב, וְאָז כּוֹתֵב לָהּ מִיָּד (טוּר):

If [the groom] is unable to write her [the bride] a ketubah, for example if it is shabbat, or he forgot to write her one, he can give her objects [which have value] in place of the ketubah, and accept responsibility if they are lost or stolen [the wife is not responsible for replacing them], and then it is acceptable for them to be together until he is able to write [a ketubah]. Rem"a: and then he must write one immediately (tur).

Se’if 3ג׳

אִם כָּתַב לָהּ כְּתֻבָּה, וְנֶאֶבְדָה, אוֹ שֶׁמָּחֲלָה לוֹ, וְדַוְקָא שֶׁכָּתְבָה לוֹ: הִתְקַבַּלְתִי כְּתֻבָּתִי, צָרִיךְ לִכְתֹּב אַחֶרֶת בְּעִקַּר הַכְּתֻבָּה, שֶׁאָסוּר לְאָדָם לִשְׁהוֹת עִם אִשְׁתּוֹ שָׁעָה אַחַת בְּלֹא כְּתֻבָּה. הַגָּה: עִיר שֶׁכְּבָשׁוּהָ כַּרְכּוֹם, אוֹ שֶׁגָּלוּ מִן הָעִיר, וְאִבְּדוּ הַנָּשִׁים הַכְּתֻבּוֹת שֶׁלָּהֶם, צְרִיכִים לְחַדֵּשׁ נְשׁוֹתֵיהֶם כְּתֻבּוֹתֵיהֶם, אַף עַל פִּי שֶׁיֵּשׁ לוֹמַר שֶׁמָּא יִמְצְאוּ אַחַר כָּךְ כְּתֻבּוֹתֵיהֶם אוֹ יַחַזְרוּ לָהֶם, מִכָּל מָקוֹם מֵאַחַר שֶׁהַכְּתֻבּוֹת בְּחֶזְקַת אֲבוּדוֹת צְרִיכִין כְּתֻבּוֹת אֲחֵרוֹת; וְאִם אֵינוֹ יָדוּעַ סַךְ הַכְּתֻבּוֹת, אִם יִשָּׁאֲרוּ קְצָתָן, אָזְלִינָן בָּתְרַיְהוּ; וְאִם לָאו, דָּנִין עַל פִּי זִקְנֵי הָעִיר וּלְפִי הַמִּנְהָג, הֶעָשִׁיר לְפִי עָשְׁרוֹ וְהֶעָנִי לְפִי עָנְיוֹ (בֵּית יוֹסֵף בְּשֵׁם תְּשׁוּבַת הַגְּאוֹנִים). וּכְשֶׁנֶּאֶבְדָה הַכְּתֻבָּה וּבָא לִכְתֹּב לָהּ כְּתֻבָּה אַחֶרֶת, צָרִיךְ לִכְתֹּב לָהּ כְּתֻבָּה גְּדוֹלָה כָּרִאשׁוֹנָה (מַהֲרִי"ק שֹׁרֶשׁ קט"ז). וְעַיֵּן לְקַמָּן סִימָן קע"ז, דִּבְמָקוֹם שֶׁאֵין מְגָרְשִׁין רַק מֵרְצוֹן הָאִשָּׁה, אֵין צָרִיךְ לִכְתֹּב כְּתֻבָּה; אִם כֵּן בַּזְּמַן הַזֶה בִּמְדִינוֹת אֵלּוּ, שֶׁאֵין מְגָרְשִׁין בְּעַל כָּרְחָהּ שֶׁל אִשָּׁה מִשּׁוּם חֵרֶם רַבֵּנוּ גֵּרְשֹׁם, וּכְמוֹ שֶׁיִּתְבָּאֵר לְקַמָּן סִימָן קי"ט, הָיָה אֶפְשָׁר לְהָקֵל בִּכְתִיבַת הַכְּתֻבָּה, אֲבָל אֵין הַמִּנְהָג כֵּן וְאֵין לְשַׁנּוֹת (כָּל זֶה דַּעַת עַצְמוֹ):

If [a husband] wrote [his wife] a ketubah and it became lost or destroyed, specifically if it was written: I accept [the payment of] my ketubah, [the husband] is required to write a new one because it is forbidden for a man to delay with his wife for a single hour without a ketubah. Rem"a: If the militia overtakes a city, or [the people] were exiled from the city, and the women lost their ketubah [documents], new ketubahs are required even though the claim could be made that they may yet find their [old] ketubot afterwards ketubahs, or they will be returned. Nevertheless, once the ketubah is presumed lost [because of such a situation], another one is required. And if the sum for the ketubah is not known, if some [ketubahs] remain, we go according to [their sums]. And if not, we judge them according to the elders of the city, and according to custom, the wealthy according to his wealth, and the destitute according to his destitution (Bet Yosef in the name of the Responsa of the Geonim). And when the ketubah is lost and he came to write for her another ketubah, he needs to write for her a ketubah as large as the original. (Maharik Shoresh 116). And look later at siman 187, and in the place that they only divorce according to the will of the woman, he does not need to write a ketubah; if so, in our time in our lands, that they do not divorce the woman by force because of the ban of Rabbenu Gershom, and it is like what was explained later in siman 119, it was possible to be lenient in the writing of the ketubah but this is not the custom, and it should not be changed (this is his own opinion).