Question Summary:
Is it allowed to open one’s spouses mail, check other personal documents if one suspects the other of commiting adultery or any other bad habit.

Question Detail:

Is it allowed to open one's spouses mail, check other personal documents if one suspects the other of commiting adultery or any other bad habit.

Answer :

In the name of Allah, Most Gracious, Most Merciful
Assalaamu `alaykum waRahmatullahi Wabarakatoh
Islam has given great importance to a person’s privacy.  This can be understood from the following hadith:
عن أبى ذر قال قال رسول الله صلى الله عليه وسلم من كشف سترا فأدخل بصره فى البيت قبل أن يؤذن له فرأى عورة أهله فقد أتى حدا لا يحل له أن يأتيه لو أنه حين أدخل بصره استقبله رجل ففقأ عينيه ما غيرت عليه وإن مر رجل على باب لا ستر له غير مغلق فنظر فلا خطيئة عليه إنما الخطيئة على أهل البيت (رواه الترمذى)
Abu Dhar (Radhiyallahu Anhu) narrates that Rasulullah (Sallalahu Alaihi Wasallam) said, “Who so ever lifts the curtains and peeps inside a house before being granted permission and sees the resident’s body parts which are not allowed to be seen, then verily he has committed an act which was not permissible for him.  If at the moment he was peeping a person saw him and poked his eyes, he will not be responsible.  If a person passes by a house without curtain and glances inside, he will not be at fault, but fault will be on the owner of the house. (Al-Tirmidhi)
Islam also teaches us to think good about others and to refrain from doubts and suspicions. It is stated in a hadith:
عن أبى هريرة أن رسول الله صلى الله عليه وسلم قال إياكم والظن فإن الظن أكذب الحديث ولا تحسسوا ولا تجسسوا ولا تنافسوا ولا تحاسدوا ولا تباغضوا ولا تدابروا وكونوا عباد الله إخوانا
Abu Hurayrah (Radhiyallahu Anhu) narrates that Rasulullah (Sallalahu Alaihi Wasallam) said, “Refrain from doubts for verily doubts are the worst lies. And do not make inquires, and do not spy, and do not have mutual quarrels, and do not have jealousy, and do not have mutual hatred, and do not have disparity, and become the servants of Allah in brotherhood.” (Muslim)
In another hadith it is narrated:
عن أبى هريرة  قال نصر  عن رسول الله صلى الله عليه وسلم قال حسن الظن من حسن العبادة (رواه أبو داود)
Abu Hurayrah narrates that Rasulullah (Sallalahu Alaihi Wasallam) said, “Good thought (of others) is from good worship.” (Abu Dawood)
Therefore, one should refrain from suspecting the husband is involved in adultery and other sinful acts.  A key factor for a successful marriage is to have trust in the spouse.  If this hadith cannot be applied to one’s spouse then to whom can it be applicable to?  A person should defend their spouse against such allegations and support them.  Instead of reading through the husband’s private mails and documents, you should adopt means that will bring both closer and create more love.  It is understandable that a wife feels threatened due to the strange behavior of her husband, and she goes through his personal details.  If she comes across any inappropriate information, she should discuss the issue directly with him and assist him to come out of his bad habits.
And Allah knows best
Wassalam
Ml. Ehzaz Ajmeri,
Student Darul Iftaa
Checked and Approved by:
Mufti Ebrahim Desai
Darul Iftaa, Madrassah In'aamiyyah