A misunderstanding

From the next room came a deafening sound of a slap. I could bear it no longer. I dashed into my room and slammed the door hard. The image of my dad slapping my mum kept wavering in my mind. The screams and sobbing seeped through the thin wall of my room and trailed me. I tried to cry out loud, but I could not. I really felt that dad was destroying this home. He had been cheating on us. I knew who this lady is. She was the one who broke up this lovely and warm home.
I always collect the mail from the stainless steel letter-box on my way home from school. I made a point to find out who had written what and could recognized the handwriting and typefaces the senders used. It was early May when I noticed a new sender. The handwriting was messy and I had never seen it before. It was addressed to my dad. Out of curiosity, I turned over the plain brown envelope and saw the name and address of the sender- Karen.
My heart nearly jumped out. I remembered hearing my dad coo on the phone with a...