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 is His slave and Messenger.
First of all, you should take it easy as it is natural for a woman to be jealous when her husband marries a second wife.
You should console yourself by remembering that this is an Islamic legislated matter and that there are many benefits in polygyny for the Muslim Nation and for the Muslim women, therefore, this general benefit should be put in priority over a personal benefit.
For more benefit, please refer to Fataawa 99522 and 86818.
If you comfort yourself with such matters, it might be that Allaah will repel from you those whispers especially the thought of committing suicide. If you continue to think about this, the devil may gradually drag you to execute this thought, and if you do so, you will be among the losers in this worldly life and in the Hereafter. For more benefit, please refer to Fatwa 84296.
Your husband is obliged to be just between you and his second wife. Therefore, you should advise him about this, as regards revealing his secret and informing his family about the matter, then you should not do so except with his permission.
Also, you are not permitted to ask for divorce unless you have a sound religious reason. How can you ask for divorce while stating that your life will be over if you do so. Besides, you should know that a Muslim is not permitted to wish to die, because the Prophet prohibited doing so.
With regard to your husband saying “I will divorce her”, this wording does not lead to divorce unless your husband intended it, as we clarified in Fatwa 92476.
If we presume that your husband intended divorce, then if he repeated this word three times as a way of confirming the first divorce, then this is considered as one divorce, but if he intended to initiate another divorce, then this is considered as three divorces according to the majority of the scholars . However, some of them are of the view that this is only one divorce. For more benefit in this regard, please refer to Fatwa 87485.
Finally, your husband may consult a scholar in your country about the matter of this divorce or any trustworthy Islamic institution so that they will find out from him the reality and give him a Fatwa accordingly.