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.
If the husband told his wife that she is unlawful to him intending divorce, then she is divorced. Moreover, if he told her that intending Thihaar, i.e. claiming one's wife to be sexually impermissible like an unmarriageable woman, then she is sexually unlawful for him like an unmarriageable woman.
Furthermore, if he told her that intending it to be a vow to urge her to do or to shun something, then it is an oath; it depends on the husband’s intention. Hence, if you told her that merely to tease her, then it is not considered a divorce or Thihaar since you did not intend any of them.
Therefore, you should expiate for breaking your oath, according to your intention, which is feeding or clothing ten poor people. However, if you can not afford that, then you should fast three days.
On the other hand, if you intended divorce while uttering those words, then the divorce is effected, even if you were in a fury, unless you were so angry that you lost control of your senses.
Furthermore, we advise you, dear questioner, to fear Allaah The Almighty and not to hasten to utter such serious words that may result in destroying your home.
Allaah Knows best.