After My Scumbag Boyfriend Betrayed Me, I Seized the Throne

You promised we would rule the realm together, yet you turned cold and heartless. I trusted you so much. I believed you could save me from my loneliness, and that you were the only one for me. But it was all an illusion you had woven. If that's how it is, then I'll show you the power and ambition of a woman! A woman who transmigrates x a man who transmigrates. They conquer the realm together and promise to be each other's one and only for life, but the scumbag turns on her. The woman kills him outright and becomes emperor herself. Theme: Relying on yourself is better than relying on others