Does a wife become forbidden to her husband if he tells her, "It is forbidden for you to enter any of the houses in this area —the city of Ma'an in Jordan— and if you do, then you are forbidden to me, and you shall not return except by marrying another man besides me," and then she enters the house of people whom they do not know?

The relied-upon fatwa is that if a man says to his wife: "You are forbidden to me," reference is made to his intention. If he intended divorce, then it is a divorce. If he intended ẓihār (a pre-Islamic form of divorce), then it is ẓihār. If he intended an oath or did not intend anything specific, then it is an oath. It appears from the question that the questioner intended three divorces by his statement "You are forbidden to me." Therefore, if the wife enters the house upon which her divorce was conditioned, she will have been divorced three times, and she will not be lawful for him until she marries another husband in a marriage of desire.