In this case, Single Judge discussed the admissibility of evidence in cases filed in Family Courts u/s 14 and also dispelled the false notion that if a spouse obtains an evidence illegally (by installing a CCTV in this case), such act would not be violative of the other spouse’s right to privacy. And also nothing in Constitution of India prohibits such evidence.

From Para 37,

37. While consistency in law is of utmost importance and law must get its full play regardless of the fact situation, this court must record the unease it feels with regard to a certain aspect that has arisen in this matter. Marriage is a relationship to which sanctity is still attached in our society. Merely because rules of evidence favour a liberal approach for admitting evidence in court in aid of dispensation of justice, this should not be taken as approval for everyone to adopt any illegal means to collect evidence, especially in relationships of confidence such as marriage. If the right to adduce evidence collected by surreptitious means in a marital or family relationship is available without any qualification or consequences, it could potentially create havoc in people’s personal and family lives and thereby in the society at large. For instance, if a spouse has the carte blanche to install a recording device in a bedroom or other private space or to adopt any means whatsoever to collect evidence against the partner, even if in circumstances of matrimonial discord, it would be difficult to foresee the length to which a spouse may go in doing so ; and such possibility would itself spell the end of the marital relationship. It is not uncommon for spouses to continue living together, even in matrimonial strife, for years on-end. So, while law must trump sentiment, a salutary rule of evidence or a beneficent statutory provision, must not be taken as a license for illegal collection of evidence.

Citations :

Other Sources :

https://indiankanoon.org/doc/170404652/

https://www.casemine.com/judgement/in/5efb8cc29fca196e33048e01

https://www.indianemployees.com/judgments/details/deepti-kapur-versus-kunal-julka

[S. 14 of Family Courts Act] Del HC | In a contest between right to privacy and right to fair trial, both of which arise under expansive Art. 21, right to privacy may have to yield to right to fair trial

Note: The nut case went to Supreme Court and the SC kicked out the SLP.