Beware of the Villainess!

Story:

I became the villain of a love affair. You think there's something wrong with me? No, it's just fine. Being the Duke's daughter allows me to live in luxury and comfort, and I'm going to take full advantage of my current situation. But although I don't want to go the antagonist way, I won't be white or fluffy either. My fiancé cheated on me with the protagonist, so I will rewrite the original story and put everyone on their knees. Those bastards aren't worth my tears.