What is incumbent upon me after I swore to my wife that she would not enter her friend's house, and I said to her: "By Allah, you will not enter this house," and then followed that with a threatening statement: "Do you know that if you enter this house, you become unlawful to me," and the wife entered the aforementioned house?

If, by this statement, you did not intend to create a new condition, but rather to clarify what follows from your previous oath, then nothing results from it, and the expiation for your first oath becomes binding upon you. However, if you intended to condition the prohibition of your wife on entering this house, then the prohibition of the wife refers back to the intention of the one who uttered it. If you intended zhihar by it, then it is zhihar. If you intended divorce by it, then it is divorce. And if you intended an oath by it, then it is an oath. Since the condition upon which you based it has occurred, then what you intended has occurred. Assuming you intended an oath, then expiation for an oath becomes binding upon you. The preponderant opinion is that expiation does not multiply with the multiplication of oaths concerning the same matter.