Yet you ask, “Why?” It is because the LORD has been a witness between you and the wife of your youth, against whom you have broken faith, though she is your companion and your wife by covenant.
KJV
Yet ye say, Wherefore? Because the LORD hath been witness between thee and the wife of thy youth, against whom thou hast dealt treacherously: yet [is] she thy companion, and the wife of thy covenant.
ASV
Yet ye say, Wherefore? Because Jehovah hath been witness between thee and the wife of thy youth, against whom thou hast dealt treacherously, though she is thy companion, and the wife of thy covenant.