All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Let us say, first of all, that a man's saying to his wife “I am not your husband anymore” is one of the metaphors of divorce; but if he does not intend divorce by it, his wife will not be divorced; and if he intends divorce, she will be divorced.
According to the words of “Al-Mudawwanah”: I (Imaam Sahnoon) said (to Imaam Ibn-ul-Qaasim): "Tell me, if a man says to his wife: “You are not my wife” will it be considered divorce according to Imaam Maalik?” He said: Maalik said: “It will not count as divorce unless he intends divorce thereby.”
In his book “Al-Ashbaah Wan-Nathaa’ir”, As-Suyooti said when counting the metaphors of divorce: 'You are not a wife of mine' according to the most correct opinion…”
But your husband’s words "till you get married to somebody else" makes it clear that he intended divorce; and he may have even intended thereby to divorce you thrice. Also, he may have meant by his word 'till you marry' that you would be able to marry another man.
In any case, writing the word of divorce effectuates a divorce on condition that the husband, on writing it, intended divorce, as has already been clarified in many previous Fataawa. For further information, see Fatwa 89894.
On that basis, the only one to define whether or not the divorce has taken place is your husband. So, he should be asked about his intention by that message: if he intended to divorce you thrice, then you have been divorced thrice, according to the majority of scholars; and if he intended to divorce you only once, the divorce then has taken place only once; and if he did not intend divorce, then you have not been divorced. However, it is better to take your case to the nearest Islamic center concerned with divorce affairs in order to consider the matter from all sides. For further benefit, please refer to Fatwa 148463.
Finally, it is noteworthy that what you have mentioned about the details of your husband's absence from you has no effect on your case if he had taken you back before the end of the ‘Iddah after divorce.
Allaah Knows best.