A few nights ago I got into a heated argument with my better half. During the course of the conversation she raised her voice, cursed me and said a large number of hurtful things. At the heat of the moment, I looked at my wife and said to myself, “I divorce you!” doing so with a clear intention. Let me clearly state that I said nothing to her at that time nor did I mention it latter. The next day cooler heads prevailed and I began to regret what I said. Then it occurred to me that I may have divorced her? Is that the case?
The Prophet [sa] said, “Allah has forgiven my nation for the inclinations in their souls which they do not verbalize or act on.” [Related by Muslim]
Based on the hadith above and your question the Malikis mention the legal axiom: “There is no divorce based on an intention unless it is spoken.” See Sharh al-Zarqani Vol. 4 Pg. 105.
Dr. Sadiq ‘Abdu al-Rahman al-Gharyani says, “Divorce does not occurred with an intention alone unless it is accompanied by words. There is no divorce based on one’s inner voice, nor does it take place due to the whisperings of the devil.” Mudawanah fi al-Fiqh al-Maliki wa al-Dilatuhu vol. 2 pg. 677
Thus, your marriage is fine and there was no divorce.
Allah knows Best