AITA for exposing my sister and my ex at a dinner meant to reunite our family?

My parents smiled as they announced that my boyfriend had chosen my older sister over me, then told me not to ruin the moment. Years later, they arrived at a dinner I was hosting and acted as though we were one big, happy family. By dessert, my mother, my sister, and my ex had all gone pale because the truth finally had a seat at my table. ---------------🦦Otter Stories🦦--------------- #reddit #stories #redditstories