Because He also said "Love Your enemies" !!!!!!

In God's eyes, once you are married and you are in a covenant relationship.

To break such a covenant (unless the other party breaks the covenant first,

by adultery in the case of the marriage covenant) brings one under a curse.

Jesus taught that divorce is only a concession God made because of the

hardness of the hearts of the people in Moses' time and is not His desire.

His desire is for one to remain in a marriage and love the spouse even if

they are as an enemy (for the purpose of winning them for Christ).