Is the husband's statement to his wife: "Don't forget that I told you if you talk to anyone other than your family on this email, you will be unlawful to me, meaning divorced," considered an oath of divorce, knowing that he had not said this before, and the wife was talking to friends on another email unknown to the husband? And what is the current status of the wife?

What the husband said ("Don't forget...") is not an oath of divorce merely by itself. If divorce was not previously conditional, then his statement has no effect. And because we do not know what the husband said previously, we cannot rule on the negation of divorce or its occurrence. Therefore, we advise you to speak directly with scholars in your country, with your husband present.