Ulangan 24:4

אחרי אשר הטמאה [HER FIRST HUSBAND … MAY NOT TAKE HER AGAIN TO BE HIS WIFE] AFTER THAT SHE IS DEFILED — these words are intended to include in the prohibition a faithless wife (סוטה) who had been in seclusion with another man (Sifrei Devarim 270:10; Yevamot 11b).

then her former husband, who sent her away, may not take her again to be his wife, after she is defiled; for that is abomination before the Lord: and thou shalt not cause the land to be sinful, which the Lord thy God gives thee for an inheritance.

לֹא־יוּכַ֣ל בַּעְלָ֣הּ הָרִאשׁ֣וֹן אֲשֶֽׁר־שִׁ֠לְּחָ֠הּ לָשׁ֨וּב לְקַחְתָּ֜הּ לִהְי֧וֹת ל֣וֹ לְאִשָּׁ֗ה אַחֲרֵי֙ אֲשֶׁ֣ר הֻטַּמָּ֔אָה כִּֽי־תוֹעֵבָ֥ה הִ֖וא לִפְנֵ֣י יְהֹוָ֑ה וְלֹ֤א תַחֲטִיא֙ אֶת־הָאָ֔רֶץ אֲשֶׁר֙ יְהֹוָ֣ה אֱלֹהֶ֔יךָ נֹתֵ֥ן לְךָ֖ נַחֲלָֽה׃ {ס}