The children can't be adopted by someone else unless you have relinquished your parental rights or the court has extinguished them (which involves a legal process; it wouldn't happen without your knowledge). If you are sure you have not done so, then they have not been adopted.
I would urge you to get help from a family law attorney to get a parenting pla in place, or if there is one already, to get it enforced. If you cannot afford a family law attorney to represent you, many will provide "unbundled services" (provide guidance to you while you represent yourself) and there are also many clinics that will help you.
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