i want to become the emperor so i need a divorce

Born as an imperial princess, Arnoah was forced to marry the pathetic young king of a small neighboring kingdom. Her older brother became the emperor, so what was she supposed to do? And due to the laws of inheritance, even if her older brother and younger brother were to die, she would still not inherit the throne - rather, her good-for-nothing cheater of a husband would!! Any title she inherits would be vested in her husband in accordance to their marriage contract... that is, until he decides to divorce her because his mistress wants to be the official queen.“I need to get divorced and become the emperor.”Her now official ex-husband still doesn't seem to get it, so she decided to finally tell him everything she always wanted to say to his face. When he realized the truth, it was already too late. She spoke to her ex-husband who had his mouth agape.“I told you to keep your head straight. Didn’t you hear me?”