Reference: Fataawa at-Talaaq – Question 28, Page 54
Question: I quarrelled with my wife, and after the quarrel I said to myself without verbally saying so: “Why don’t I just say to her: “You are divorced!”?” [So I made my mind up and thought] I shall say to her: “You are divorced!” So, is there anything upon me as a result of this? Keeping in mind that I did not verbally say anything. {Please} provide me with a fatwa, [and] may Allaah reward you with good.
Response: If the situation is as described in the question, then the divorce is not applicable. This is because the divorce is not applicable by just the intention, rather it applies if it is written or [pronounced] verbally, as the Prophet ﷺ said:
«Indeed Allaah overlooks the affairs of my ummah, so long as it has not done the act or spoken [about it]». From the hadeeth of Abu Hurayrah (radhi-yAllaahu ‘anhu) of which its authenticity is agreed upon by both Imaam al-Bukhaaree and Imaam Muslim.