I came to visit my husband who lives in a different country with his other wife. When I arrived he started dividing nights between us even though I only came to visit him for one month. Is this fair and in accordance with Islam?
Bismihi ta'ala
If your husband lives in a different country, and you have given approval for that, and not objected, then this does not deprive the other wife from her right when you visit him.
It would be good if the other wife forgoes her time during this period, and you have enough time to spend with your husband, but if she refuses, then she has that right. Unless, of course, such a condition was stipulated in your marriage contract, in which case the husband must abide by it.
Whatever the situation may be, the main issue is whether or not it is good for you to be away from your husband for long periods of time, and when visiting him how much time you have with him.
Nothing is more important than fairness and facilitating all the due rights of others.
With prayers for your success.