Husband sharing his nights equally between his wives

It is compulsory upon the husband to share his nights equally between his wives. The method of equal distribution is left to the discretion of the husband, (for example if he spends three nights with one wife, it is compulsory upon him to spend the next three nights with the other wife. If he wishes to spend two nights with one wife, it is compulsory upon him to spend the same amount of time with the other wife). The night commences from sunset and ends at subh saadiq (dawn). As far as the time during the day is concerned, it is preferable for the husband (though not compulsory) to share his time equally between his wives.

And Allah Ta'ala (الله تعالى) knows best.