All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
If when that wife purchased the TV set she knew that her husband was not concerned about whether what he would watch were lawful or unlawful, then she is sinful. In that case, she must repent to Allaah and whoever sincerely repents to Allaah, Allaah will accept his/her repentance. For more benefit, please refer to Fatwa 86527.
However, if she did not believe that it was likely that her husband would watch forbidden thing on the TV, then she is not sinful.
Moreover, she should strive to correct her husband and not despair. She should supplicate Allaah as much as possible to give her the ability to do so.
If her husband takes heed and treads the path of righteousness, then this is what is desired; otherwise, she is not obliged to destroy the television. She should try to deal with her husband in a wise and appropriate manner and she may make use of some pieces of advice that we have mentioned in Fataawa 50623 and 98765.
Allaah Knows best.