Luke 16:18 question. thanks?

Matt. 19:8, 9: “[Jesus] said to them: ‘Moses, out of regard for your hardheartedness, made the concession to you of divorcing your wives, but such has not been the case from the beginning. I say to you that whoever divorces his wife, except on the ground of fornication [extramarital intercourse], and marries another commits adultery.’” (So the innocent mate is permitted, but not required, to divorce a mate who commits “fornication.”)