Rose Among the Ruins by Ariel Tachna
After almost a generation of war, peace has come at last through the political marriage of a Mordyn princess to the prince of Ageselm. While escorting the bride, comrades-in-arms Rhicer and Kanath inadvertently drink a love potion intended for the newlyweds—and find themselves dealing with newfound desire for one another. As they struggle with their growing connection in a culture that despises same-sex love, Rhicer and Kanath face a terrible decision: give in to the social mores of their time and abandon love or answer the call of their hearts and leave Ageselm forever.
how to magically make him gay..