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.
We have already issued Fatwa 87877 clarifying that a husband is not permitted to suspect his wife without evidence and that the wife should close any door that makes her husband suspect her; so please refer to the above Fatwa.
Your husband should have asked you about the matter and dealt with it calmly and not hastened for divorce. In addition to this, divorce is not the only solution to marital problems.
However, if he had written the words of divorce while intending to initiate divorce, then divorce took place. For more benefit on writing the word divorce, please refer to Fatwa 89894.
If this is the first or second divorce, then he can take you back without a new contract as long as you are still in your waiting period. If your waiting period expired, then he is not permitted to take you back except with a new contract, the consent of your guardian, a dowry and the presence of two witnesses. For more benefit on the kinds of divorce, please refer to Fatwa 82541.
Finally, it should be noted that both spouses should have mutual understanding and respect, and each of them should know and fulfill the rights of the other.
Allaah Knows best.