All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.

 

If the case is as described in the above question, then the wife shouldn`t be separated from her husband because the Shafi and Hanbali doctrines stipulate five sucklings and more to make the marriage unlawful while, in this case, there are only two confirmed sucklings since having doubt about a third one makes it as good as none. They have based this view on the following Hadiths: Narrated 'Aishah (RA): Allah's Messenger (Peace and blessings be upon him) said: "One or two sucks do not make (marriage) unlawful." [Muslim reported it]. He (Peace and blessings be upon him) also said: "Umm Fadl (Allah be pleased with her) reported Allah's Apostle (may peace be upon him) having said this "One or two sucklings do not make (the marriage) unlawful." {Sahih muslim}.

Moreover, ‘A’isha (May Allah be Pleased with her) said: "in what was sent down in the Qur’an ten known sucklings made marriage unlawful, but they were abrogated by five known ones, and when God’s Messenger died these words were among what was recited in the Qur’an." {Muslim transmitted it}.  What was sent down in the Qur’an" refers to the legislation sent down on the Messenger of Allah (Peace and blessings be upon him). This is in addition to many an evidence stated in the books of both doctrines (Shafi and Hanbali). 

It is true that there doctrines which stated that one suckling makes marriage unlawful, but when a marriage has been formalized, spouses shouldn`t be separated unless there is unanimous agreement that their marriage is invalid.

In conclusion, based on the above your daughter (Questioner`s) shouldn`t be separated from her husband. And Allah The Almighty Knows Best.