What is the ruling on a wife asking her husband to travel to her and reside with her, or on her agreeing with him that he divide his time between her and the first wife, night by night, in the absence of the first wife?

The implications of a husband who has more than one wife traveling, concerning whether he chooses who travels with him or if it is obligatory to cast lots and make up for the one who did not go, is a matter of disagreement. The husband spending the night with the wife he traveled with every night, and leaving one night [from that arrangement], does not preserve the right of the other wife. It is not permissible for the husband to be absent from his wife for more than six months without a legitimate excuse or her permission.