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.
The husband is not allowed to prevent his wife from using the phone without a valid reason such as her speaking with a non-Mahram man or using it in a way that brings about potential harm or evil of any kind. In this case, the husband may prevent her from using the phone because he is in charge of her and for the sake of commanding right and forbidding wrong, just as he would prevent her from anything that brings about harm to her. If the husband prevents his wife from using her phone out of jealousy, it should be noted that there is a praiseworthy jealousy and a blameworthy one. The praiseworthy jealousy is that based on justified reasons, while the blameworthy is that which is not based on mere suspicion, as scholars have said. For more benefit, please refer to Fataawa 90757 and 237010.
We advise married couples to foster mutual trust and love. The husband should have confidence in his wife and the wife on her part is advised to avoid situations of suspicion and temptation so as not to open the door for suspicions that could ruin her marital life. She is also advised to observe modesty, keenly preserve her religiosity and keep the company of righteous female friends in order to gain her husband's love and trust.
Allaah Knows best.