Mishnayos Yevamos Perek 14 Mishnah 9

If two brothers, one of whom is a deaf-mute and the other one halakhically competent, were married to two unrelated women, one of whom is a deaf-mute and the other one halakhically competent, and the deaf-mute brother who was married to the deaf-mute woman died, what should the halakhically competent brother married to the halakhically competent woman do? He may marry her if he desires the deaf-mute woman, and if he wishes afterward to divorce her, he may divorce her. If the halakhically competent brother married to the halakhically competent woman died, what should the deaf-mute brother married to the deaf-mute woman do? He marries his yevama and may never divorce her, as he does not have the legal capacity to end a valid marriage.

שְׁנֵי אַחִים, אֶחָד חֵרֵשׁ וְאֶחָד פִּקֵּחַ, נְשׂוּאִים לִשְׁתֵּי נָכְרִיּוֹת, אַחַת חֵרֶשֶׁת וְאַחַת פִּקַּחַת, מֵת חֵרֵשׁ בַּעַל חֵרֶשֶׁת, מַה יַּעֲשֶׂה פִקֵּחַ בַּעַל פִּקַּחַת, כּוֹנֵס. וְאִם רָצָה לְהוֹצִיא, יוֹצִיא. מֵת פִּקֵּחַ בַּעַל פִּקַּחַת, מַה יַּעֲשֶׂה חֵרֵשׁ בַּעַל חֵרֶשֶׁת, כּוֹנֵס, וְאֵינוֹ מוֹצִיא לְעוֹלָם: