"I was supposed to never love you"

I dreamed of a romance with a small and cute princess, but it was me—large and not cute at all, age 10—who became the fiancée of the 8-year-old prince. He told me, "I will never love you!" and I became his temporary fiancée until the prince found someone he truly loved. Four years have passed since then. I thought we had been getting along reasonably well, but now there are rumors that the prince is growing close to the next Holy Maiden...