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.
You mentioned that your husband had pronounced divorce in anger in all the three cases. There are different situations regarding an angry person:
In some cases, his divorce is effective according to the agreement of the jurists. In other cases, his divorce is not effective according to their agreement as well. Yet in other situations, the scholars hold different opinions, whether or not his divorce is effective. For more benefit, please refer to Fataawa 121374 and 83467.
We do not know the situation of your husband in the three divorces that he had uttered. We also do not know the exact wording of divorce that he had uttered, and whether it is an explicit word of divorce or a metaphor. In case it was a metaphor, did he intend divorce or not?
This is in addition to the fact that the validity of taking the wife back (after divorcing her) by means of having sexual intercourse with her is also an issue about which the scholars differed.
Therefore, we cannot assert whether or not you are still in bond of marriage with your husband. Thus, it is better if your husband would orally ask one of the trustworthy scholars in your country or consults one of the Islamic Centers in this regard.
Since he has promised you not divorce you, then fulfilling the promise is desirable according to the view of the majority of the jurists but not obligatory.
If by your question you are comparing between promises and divorce, and you think that the promise can prevent the divorce from being effective, then this is a wrong. If your husband had uttered divorce, then it takes place even if he has promised to keep you in bond of marriage his whole life.
It should be noted that the husband should avoid uttering divorce and not making it a way of solving marital problems, as he may regret it.
He should also avoid anger as much as possible, as this is a dangerous means for the devil to influence the person. It is for this reason that the Prophet advised one of his companions not to get angry, and he clarified how to treat anger.
For more benefit on how to treat anger, please refer to Fatwa 86681.
Also, refer to Fataawa 243088, 245707, 233290, and 220696 for cases of divorce issued in anger.
Allah knows best.