My wife asked for divorce about 30-years ago. I tried very hard to stop her, but all efforts closed. Even though I feel that she was wrong in refusing settlement but I want her to forgive me before I die. I was told that a Muslim should be free of all human wrong doing before he or she leave this earth.

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

One of the conditions for the validity of repentance from wronging or taking the right of other people is that the person should ask forgiveness from them. The Prophet said: "If someone has wronged a person with regard to his dignity, or honour, he has to seek forgiveness today before comes The Day where there would be no Deenaar nor Dirham.  On that Day, if a person has good deeds, then they will be taken from him according to the extent of wrong he did to another person, and if he has no good deeds, then the bad deeds of the person he wronged will be taken off him and transmitted to the transgressor." [Al-Bukhari]

So if you had been negligent towards the right of this woman, then you have to seek forgiveness from her if that is still possible, provided that one does not find himself in a state of suspicion, because we understand from your question that you divorced her long ago. However, if that is not possible because you do not know where she is and the like, then you are obliged to supplicate and seek forgiveness for her as much as possible. This is of course if you had really wronged this woman, otherwise you are not sinful and you are not required to do anything.

Allaah knows best.