Parents are away, sisters push each other to fuck

When my parents were away, my two sisters pushed each other to fuck each other. My father married a woman who was already married and now has an adult daughter, so that girl became my step-sister. At school, I was a bad guy, so the person I secretly liked also loved someone else. It was so sad that when I got home, I could only confide in my step-sister. My sister was also very willing to help me by secretly flirting with me so that I could forget my sadness.