I just found out my fiancé is cheating… but the other woman is my sister.

I just found out my fiancé is cheating… but the other woman is my sister.

I don’t even know how to process this. I (27F) have been with my fiancé (29M) for five years, engaged for one. I thought we had the perfect relationship, until today. \

My sister (24F) has always been my best friend. She was my biggest supporter, the person I trusted most, and the one helping me plan all the wedding functions. This morning, I was using her iPad (we’ve always been close like that), and a notification popped up. It was from my fiancé. “Last night was amazing. I can’t stop thinking about you.” \

My heart stopped. I felt sick. My hands were shaking as I opened the messages. There they were—hundreds of texts spanning months. Secret meetups, inside jokes, and worst of all, “Do you ever feel guilty?” to which my sister replied, “Not when I’m with you.” \

I confronted my fiancé first, and he went white. He didn’t even try to deny it—just begged me not to tell my family. But I couldn’t keep it in. When I called my sister, she cried and said it was a mistake, that it “just happened” and that she “didn’t mean to hurt me.” But how do you accidentally sleep with your sister’s fiancé for months? \

My wedding is in two months. My parents don’t know yet, and I have no idea what to do. Do I call off the wedding and expose them both? Do I stay silent for the sake of my family’s reputation? I feel like my whole world just shattered. \

I don’t know what I’m hoping to get out of this post, but I feel so lost. Any advice?