A misunderstanding occurred between me , my in-laws and my children. They were unfair to me, and I took an oath that my wife was now prohibited for me, and she could only return to her father's house as a divorcee. After some time things cooled down, and they asked me for forgiveness. I considered that it was part of goodness for me not to prohibit my wife from having contact with her children and me, and she returned home. My question Shaykh is: Was my wife considered divorced by her return to her father's house? What is the ruling of taking an oath which states that my wife is prohibited for me? May Allah bless you, and grant you light. هدد زوجته بالطلاق

All praise is due to Allah. May Allah's peace and blessings be upon the Messenger of Allah, his family and companions.
To proceed:
To answer your question I say:
Firstly: I advise you to fear Allah, and to use the divorce pronouncements in issues like this. As for what happened; the way out is that you should expiate for the oath because what is apparent from your question is that you mentioned divorce in order to prevent your wife from going to her family's house. The ruling for such cases is the ruling of the oath according to the preponderant opinion of the scholars. As for a man's telling his wife, "You are prohibited to me;" this is prohibited, and Allah the Exalted criticized His Messenger for prohibiting what Allah has permitted. Allah said, " O Prophet, why do you prohibit [yourself from] what Allah has made lawful for you" [at-Tahrim: 1].  Thus the way out  from this is through what was mentioned in Surah at-Tahrim, and that is the expiation for an oath because Allah said, " Allah has already ordained for you [Muslims] the dissolution of your oaths" [at-Tahrim: 2]. Thus, it is imperative for the person who utters this statement to expiate his oath, and this is what was mentioned by Allah in His statement: " Allah will not impose blame upon you for what is meaningless in your oaths, but He will impose blame upon you for [breaking] what you intended of oaths. So its expiation is the feeding of ten needy people or from the average of that which you feed your [own] families or clothing them " [al-Maaidah: