Answer
(Fatwa: 372/304/B=1433)
When the husband wrote talaq three times in the talaq paper and sent it, then all the three talaqs took place and the wife became mughallazah bainah. In order to marry the same husband again a Shariah halalah is necessary. It is mentioned in the holy Quran clearly:
فَإِن طَلَّقَهَا فَلاَ تَحِلُّ لَهُ مِن بَعْدُ حَتَّىَ تَنكِحَ زَوْجاً غَيْرَهُ .
Also there is a Sahih hadith in Abu Dawood Sharif that a Sahabi divorced his wife three times in the presence of the holy Prophet Muhammad (صلى الله عليه وسلم) in single meeting, then the holy Prophet Muhammad (صلى الله عليه وسلم) counted it three. The fatwa which your husband brought that all the three talaqs of the talaq paper are void, it is totally wrong and against the holy Quran and Hadith. It is adultery and haram for the woman to live with him, she should separate herself from the man.
Allah (Subhana Wa Ta’ala) knows Best
Darul Ifta,
Darul Uloom Deoband