My step-brother forced himself on me

Dear Lolade, I am 15 and the only child of my mother who remarried about three years ago. We moved into her new husband’s home and sometime last year, my step-brother, who is now 18, forced me to have s3x with him. Whenever my mother and step- father go to our home town, which is at least once a month, he forces himself on me. When it first happened, I threatened to tell my mum. He laughed and threatened to harm me if I did.

When I eventually had the courage to tell my mum, that my stepbrother was touching me, she said I was trying to break up her marriage because I didn’t like my step-father. My mum told me my step-brother merely had a crush on me and I was being silly. I’m scared of what would happen if I told her that he was actually having s3x with me.