Does a wife forfeit her right to her husband's overnight stay (mabīt) if she goes to her family's home with her children to complete her studies, given that it is 20 kilometers away from her husband's home?

If a husband gives his wife permission to go to her family's house and stay with them for a period, her right to a share of his time (qasm) for that period does not lapse, because the distance is usually not considered a travel (safar) in Islamic law. If it is considered travel, there is a difference of opinion among scholars regarding the lapse of her right to a share of his time, and the preponderant view is that it does not lapse.