He gave her wife two Khul' and wants to remarry her after her divorce from another man
3-1-2018 | IslamWeb
Question:
Assalaamu alaykum. My wife gave me a Khul‘ (divorce requested by the wife in return for a compensation), and she got married to another man after six months and gave him a Khul‘ after being with him for two months. She got married to me again and again gave me a Khul‘. It has been seven months since we got divorced, and she now wants to come back to me. The question is: is it halal for me to get back with her, and is this the last time, after which she becomes unlawful for me to marry, or do I have two more times given that she married another man after giving me a Khul‘ the first time? May Allah reward you.
Answer:
All perfect praise be to Allah, the Lord of the worlds. I testify that there is none worthy of worship except Allah and that Muhammad 
is His slave and Messenger.
The scholars differed in opinion concerning the ruling on Khul’ and whether it is a divorce or an annulment of the marriage. The majority of scholars held that it is a divorce.
Ibn Qudaamah 
said:
"There are different narrations from Ahmad on the Khul‘; one of the two narrations states that it is an annulment of marriage. This is the view chosen by Abu Bakr, and it is the statement of Ibn ‘Abbaas, Taawoos, ‘Ikrimah, Is-haaq, Abu Thawr and one of the two views of Ash-Shaafi‘i. The second narration is that it is an irrevocable divorce. This was narrated from Sa‘eed ibn Al-Musayyib, Al-Hasan, ‘Ataa’, Qabeesah, Shurayh, Mujaahid, Abu Salamah ibn ‘Abd Ar-Rahmaan, An-Nakhaa’i, Ash-Sha’bi, Az-Zuhri, Mak-hool, Ibn Abi Najeeh, Al-Awzaa‘i, and the scholars of the Hanafi School." [Al-Mughni, 7/328]
The preponderant opinion in our view is that of the majority of the scholars, that the Khul‘ is an irrevocable divorce [i.e. you can only take your wife back with a new contract and a new dowry, unless this was the third divorce].
For more benefit, please refer to fatwas 157545 and 88502.
The scholars also differed in opinion concerning the ruling on a woman who remarried after she was divorced less than three times by her first husband and then she returns to her first husband. Does she return to him on the basis of what remains of the divorces from him or does she return on the basis of three divorces? The view of the majority of the scholars is that she returns to him on the basis of the remaining divorces.
Ibn Qudaamah said:
"The third: if her husband divorces her less than three divorces, and she finishes her waiting period and then she marries someone else, and then her first husband marries her again [i.e. after she is divorced from her second husband]; there are two narrations from Ahmad: one narration is that she returns to him on the basis of the remaining number of divorces ... This is the view of the prominent Companions of the Messenger of Allah : ‘Umar, ‘Ali, Ubayy, Mu‘aath, Imraan ibn Husayn, and Abu Hurayrah. This was also narrated from Zayd and ‘Abdullah ibn ‘Amr ibn Al-‘Aas; and this is the view of Sa’eed ibn Al-Musayyib, ‘Ubaydah, Al-Hasan, Maalik, Ath-Thawri, Ibn Abi Layla, Ash-Shaafi‘i, Is-haaq, Abu ‘Ubaydah, Abu Thawr, Muhammad ibn Al-Hasan, and Ibn Al-Munthir. The second narration from Ahmad is that she returns to him on the basis of three divorces. This is the view of Ibn ‘Umar, Ibn ‘Abbaas, ‘Ataa’, Shurayh, Abu Haneefah, and Abu Yoosuf." [Al-Mughni, 7/505]
Accordingly, the view of the majority of scholars is that if you marry this woman again, then she returns to you on the basis of one remaining divorce, and this is the preponderant opinion in our view.
Allah knows best.