Does a final divorce (talaq bain) occur to a wife in the event of verbal or physical infidelity, or marriage to another woman, based on the husband's acknowledgment of such, and what is the ruling on this acknowledgment when a second wife exists?

If you did not utter the conditional divorce but wrote it down without intending to effect the divorce upon the fulfillment of the condition, then the divorce does not occur by your marriage to another woman or by an act of infidelity. However, if you uttered it or wrote it down with the intention of effecting the divorce, then the majority of scholars believe that the husband does not have the right to revoke a conditional divorce. This is the fatwa, and accordingly, if you marry another woman or commit the aforementioned infidelity, her divorce takes effect. What is considered in defining infidelity is your intention and purpose. Scholars have differed regarding one who says to his wife: "You are irrevocably divorced with one pronouncement." Some consider it an irrevocable divorce, while others consider it a revocable divorce. The preponderant opinion for us is that it is a revocable divorce. Therefore, if the divorce occurs and it is not the third pronouncement, you may take your wife back during her iddah without the need for a new marriage contract.