The Sultan of Yogyakarta does not plan to take a second wife.
Sri Sultan Hamengku Buwono X, the governor of the Special Region of Yogyakarta, Daerah Istimewa Yogyakarta (DIY), and the head of the Yogyakarta Kraton and the sultanate of Ngayogyakarta Hadiningrat, says, as a man, he would like to have more than one wife but he is afraid of doing so.
Sri Sultan Hamengku Buwono X
Polygamy, HamengkuBuwono also admits, was a common practice of his predecessors but he fears that he would not be able to fulfil the requirements of Islam for polygamy, that is, in being fair to both/all wives. The problem, he says, is that he cannot be sure of the feelings of the women involved, even though he might believe that he has acted fairly he cannot guess how his wives will adjudge his actions.
It’s hard enough with one wife, the Sultan says, he hurts her feelings without knowing exactly what he has done wrong. He said: 
When thinking about it like that I don’t want to be polygamous even though my religion, Islam, allows a man to have more than one wife, up to four.
(Dengan pertimbangan semacam itu maka saya tidak akan melakukan poligami, meskipun agama saya (Islam) memungkin seorang laki-laki beristri lebih dari satu hingga empat orang.)
Another factor he said was that women today were a lot more independent than in the past and they demanded to be treated the same as men.
Finally, he said that if it were announced that he taken a second wife he was sure that the palace would be quickly surrounded by angry women demonstrators. He was “owned” by the people and couldn’t just do whatever he liked.