I married a woman and we have a child together who is six years old. My wife was divorced by a court judge…

I married a woman and we have a child together who is six years old. My wife was divorced by a court judge against my will, while I had no power or choice, and I myself did not pronounce a religious divorce. The question is: Is the divorce issued by the court judge valid? After some time, my wife married another man—so is her marriage valid while she is still, in fact, my wife according to Islamic law? Now she has a child from this man; what is your ruling on this matter?