Divorce Simply by Intention Does Not Count
Question :
I had an argument with my wife and after the argument, I said to myself, without speaking the words: "Why do I not say to her: "You are divorced."? I will say to her: "You are divorced." Is anything incumbent upon me because of this, bearing in mind that I did not pronounce anything? Deliver a verdict for me, and may Allah reward you with goodness.
Answer:
If the situation is as you have described it in the question, then the aforementioned divorce is not counted, because divorce with only an intention does not count. Divorce only counts by speech or by writing, according to the words of the Prophet ﷺ:
"Indeed Allah disregards for my community what occurs within themselves, as long as they do not act upon it nor utter it."
Narrated by Al-Bukhari and Muslim from the Hadith of Abu Hurairah, may Allah be pleased with him.
Source:
Ibn Baz
Fatawa Islamiyah, Vol. 6 Pages 47-48