If my wife does what she swore not to do while she is menstruating, what is the ruling on divorcing her?

The summary of the answer: The majority of scholars hold that if a husband makes his wife's divorce conditional upon an event, then if that event occurs, his wife is divorced, whether the husband intended to effect a divorce or merely intended to threaten, emphasize, or prevent. This is the fatwa given. Some scholars are of the opinion that if he did not intend to effect a divorce but rather intended to threaten, emphasize, or prevent, then divorce does not occur upon the fulfillment of the condition, but rather an expiation for an oath (kaffarat yamin) becomes obligatory upon him. Accordingly, the fatwa given is that the divorce has occurred due to the wife's action upon which her divorce was made conditional. If the husband has not completed three divorces, he may take his wife back (raj'a) before her 'iddah (waiting period) expires.