He has a nephew, whom he chose as an heir. Look +/- 2 chapters back.
Hes attempting to cut off the cursed bloodline.
He hopes that by taking only one mate/man as his partner then there is only 1 to take the throne after him.
He also hopes that his nephew will never manifest the curse so it fully dies out.
Easy, he has brothers (Nashid) XD who already got a lover and a child. Shuraka has plans in ending the family curse anyway so he has no plans of fathering an heir bcoz they might manifest it.
It’s hot watching them want each other but…how could he be king if he won’t have an heir? Unless he would take in other concubines who would bear heirs. How’s the author gonna solve that problem?