Husband, I'm Missing in Your Life. This book fits the plot you described. The female protagonist in the story was once an empress. After being killed, she was reborn into the modern world, but she accidentally traveled back to ancient times. She met a prince who looked very similar to her former husband. They met by accident and in the end, the female protagonist used her body to save him. This novel was a modern romance novel about entertainment stars. It was very worth reading. I hope you like my recommendation, muah ~