All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
If it is not proven that your husband wrote the word divorce, then the basic principle is that he did not write it.
Therefore, the basic principle is that the marital bond continues until it is proven that it does no longer exist. The writing of divorce is one of its metaphors, so it depends on the intention of the husband. If we assume that he remembered writing divorce, then divorce does not take place unless he wrote it while intending to issue divorce. However, he does not remember that he wrote it, let alone that he intended it.
Finally, we would like to draw your attention to the two following matters:
Firstly, you should avoid problems in marital life, and that respect and understanding should prevail between spouses.
Secondly, avoiding anger, because it is the root of many evils, and that is why the Prophet sternly warned us against it.
For more benefit on divorce given in anger, please refer to Fataawa 220696, 243088, 322960, 388225, and 395773.
Allah Knows best.