Does a divorce take effect with the words "Consider yourself divorced from now on" if the husband does not intend divorce, and is pre-marital seclusion considered a consummation that entails its rulings, and how can the wife be taken back if a divorce has occurred?

Divorce via a text message is treated the same as written divorce. If the husband intended it, it takes effect; otherwise, it does not. The husband's statement, "Consider yourself divorced," is a metaphor (kinayah) and not an explicit (sarih) declaration. If you did not intend divorce with the message, then the divorce does not occur, and you are not obligated to take back your wife. However, if you intended to effect a divorce to overpower your wife, then it is effective, and your regret does not prevent its occurrence. You can take your wife back during her waiting period ('iddah). Private seclusion (khalwah khassah) is considered equivalent to consummation (dukhul) according to the majority of scholars, and consequently, the waiting period ('iddah) becomes obligatory, and the wife is entitled to her full dowry. A return (raj'ah) is valid without witnesses.