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.
Since you proved to your husband what he requested from you, then it appears to us that divorce has taken place, because his answer to you “I agree”, means that “If this thing is proved to me, then it is considered one of your divorces.”
The Indian Fatwa reads:
"If she (the wife) says: ‘divorce me [i.e. in the future] for such and such a thing, and he said: ‘Yes.’; then it is nothing because it is a promise, contrarily to her saying “I am divorced for one thousand [an amount of money], and he said: ‘Yes’; then divorce takes place; it is as if he said: “Yes, you are divorced for a thousand.” [End of quote]
Al-Ikhtiyaar fi Ta’leel al-Mukhtaar reads:
“If another person says to someone “If you do not give me my right today, then your wife is divorced’; and he replied to him saying ‘Yes’, and he meant giving him an answer (for what he said), then his oath is fulfilled because the answer requires repeating the question; it is as if he said: “Yes, my wife is divorced if I do not give you your right.” [End of quote]
However, this oath does not lead to more than one divorce; so one divorce has taken place, and two more divorces remain.
This is of course if we presume that your husband had intended divorce, but if he had intended a promise to divorce you in the future, then in this case, his divorce did not take place, because the promise of divorce does not entail divorce.
Allah knows best.