“mate.” The Hebrew word literally means “friend, companion,” but in this case it refers to the woman’s husband. It would be confusing to the modern reader to say she had left the friend of her youth, and because the “friend” is obviously her husband we went with “mate” (cp. M. Fox, Proverbs). However, there is an important lesson in that the person we marry is supposed to be our best friend and companion. In biblical times, marriages were arranged, and often the young man and woman had never even met each other before their wedding. It was taught in the culture that love developed after marriage, not before it, and that has been shown to be true in many cultures.
“the covenant she made before her God.” The Hebrew text reads that the woman forgot “the vow of her God,” and the genitive “of” can grammatically refer to a covenant made with God or a covenant made before God such that God is the witness. Since the context here is the marriage covenant, the covenant is made between the man and the woman before God, i.e., with God as a witness.