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.
One of the established rules of jurisprudence is that certainty cannot be overruled by doubt. In your case, the continuity of the marital bond is certain, and thus if the matter upon which divorce is conditioned is unknown, then you are still in bond of marriage with your husband. Ibn Qudaamah said: “… A confirmed marriage does not end with divorce that is doubtful.” [End of quote]
The saying of your husband (about you): “I am going to divorce her”, is a promise of divorce and divorce does not take place with it. Shaykh Ibn Taymiyyah said: "The promise of divorce does not occur even if the words to express it are so many. It is neither an obligation nor recommended to fulfill this promise." [End of quote]
Similarly, his saying: “I divorce her”, is also not an explicit word of divorce, so it depends on the intention of the husband. If the husband does not know that he uttered it, then it is with greater reason that he does not know his intention, if we presume that he ever had uttered such words.
To conclude, the bond of marriage is still ongoing between both of you, so deal with the other kindly and maintain a good marital relation. Allah Says (what means): {And due to the wives is similar to what is expected of them, according to what is reasonable. But the men have a degree over them [in responsibility and authority]. And Allah is Exalted in Might and Wise.} [Quran 2:228]
Each one of you should be keen on fulfilling the rights of the other, and your husband should be careful not to take the issue of uttering the words of divorce lightly, as he may regret this afterwards.
Allah knows best.