What is the legitimate position regarding a husband's relationship with his wife, whose betrayal he discovered with his younger brother, and he lives with her in the same house to protect their children, but he does not speak to her or sleep with her, and he spends one night with her and another night with his other wife? Is he obligated to be just between the two wives?

The marital bond is presumed to remain intact and is only dissolved by divorce or khulʿ. Your feeling that a divorce has occurred does not make it a reality unless you have actually divorced her. If your wife's infidelity is proven, she has committed a grave transgression. Therefore, gently advise her to repent. If she repents and rectifies her conduct, then keep her and treat her kindly. If she persists in her state, it is recommended to divorce her, as there is no good in keeping her. As long as she is under your marital bond, you must be just between her and your other wife, and her right to equal division of time (qasm) is not forfeited due to her infidelity. We emphasize divorcing her if she does not repent to her Lord.