What is the ruling on a wife leaving her husband's house without his knowledge, and repeating this five years into the marriage?

It is incumbent upon both spouses to live together amicably. The wife must obey her husband in matters that do not involve disobedience to Allah. This includes not leaving the house without his permission. If the wife disobeys her husband, he may discipline her through admonition. If that is ineffective, he may resort to boycotting her in bed. If that too is ineffective, he may resort to non-injurious physical discipline. Insulting and reviling the wife is not a path to reconciliation; rather, it leads to discord and may even be grounds for divorce initiated by the wife. It is advisable to involve wise individuals to mediate and reconcile between the spouses.