PLEASE_WAIT
The answer given to your question by Ayatollah Mahdi Hadavi Tehrani is as under:
1. Talaq Khula is "Talaq Bayin" (irrevocable divorce) and it is not possible for the husband to return to his wife during Iddah (waiting period) except for when the wife takes back what she had given him for the divorce in which case the man can rejoin his wife and there is no objection in it.
2.If the sexual intercourse after the year 2003 (following the Khula divorce) had been without the woman taking back the surrendered property, the man's return is invalid and the woman is considered as divorced. The new marriage contract is in order. In case, the intimate relations take place after the woman's taking back the surrendered property, the return (rejoining) is in order and the woman is considered to be the first man's wife and the new marriage contract is void.