If a person says, "I will consider it a divorce and review it," does that make the divorce effective, especially after he uttered a phrase not knowing whether it constituted a divorce or not, and then it later became clear to him that it was not a divorce?

Your statement, "I will consider it a divorce," and your precautionary return to your wife, do not result in the divorce taking effect. If a man makes his wife's divorce conditional upon something, and then believes the condition has occurred, and says, "Go, for you are divorced," but then it becomes clear that the condition did not occur, the divorce does not take place. Similarly, if he takes his wife back fearing that a divorce has occurred, or believing it has occurred, the divorce does not take place.