We were me and my wife both born Ahmadis. However I have left the Ahmadiyya quite publicly with the publication of articles,- etc. My wife decided to follow me out but her prime motivation was to keep the marriage.
We were have separated on and off since 1999 and I have pronounced the Islamic Talaaq on various occasions, definitely more than three. I have not had marital relations with her for the last three years. My worry about my children is one of my prime factors for marrying a Muslim lady.
1) Please tell me that Talaaq is authentic or not?
2) If I got a married with other lady there is any problem or not?
3) My first wife did not accept this Talaaq.
Kindly give me advice.

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.

In Islamic legislation divorce is in the hand of the husband. He is the one who can divorce his wife. So if you have uttered the word divorce to your wife willingly while in a sound state, then she is divorced whether your wife accepted this divorce or not. Since this divorce has taken place more than three times then she is not lawful to you unless she marries another man who would consummate the marriage with her and then divorces her or dies. This is, of course, if she sincerely repents but if she remains on her diverted belief she is not lawful to you in principle.

As regards marrying another Muslim woman, this is permissible and you should marry a religious Muslim woman who has a good moral character.

Allaah knows best.