Answer
(Fatwa: 1753/1638=D/1429)
When you gave three divorces to your wife, she was separated by talaq mughallaza (irrevocable divorce), the marriage bond of both of you was eliminated. Her iddah period will be over after three menses or after the childbirth if she was pregnant. After the iddah, she is free to marry any other man she wants except you. If she marries another man and also does intercourse, then if her husband dies or gives divorce to her, she will have to pass her iddah and thereafter she has right to marry. If she likes, she can marry you also in the presence of two witnesses with mahr, this is called Halala Shariah which is mentioned in the Holy Quran thus: فلا تحل له من بعد حتی تنكح زوجا غيره
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband