From the Council of Toledo, A.D. 681

Canon VIII. It is the precept of the Lord that, except for the cause of fornication, a wife ought not to be dismissed by her husband. And therefore whoever, apart from the fault of the crime aforesaid, has left his wife on whatever occasion, because he has determined to separate those whom God has joined, let him, deprived of ecclesiastical communion and alien from the assembly of all Christians, remain so long as he both returns to the society of the wife left behind and sincerely embraces and cherishes the part of his body by the honorable law of marriage.