Mom's Diary That Destroys Me

My mom has a strange diary.

Over the years, whenever someone treats me well, my mom makes them read this diary.

I don't know what's written inside. I only know that everyone who reads it, without exception, distances themselves from me and turns to fawning over my sister instead.

Later, I met my fiancé.

He swore to me that no matter what happened, he would always stand by my side.

I believed him.

Until my mom handed him that diary.

Just half an hour later, he became a completely different person.