My mums boyfriend recently left her and his 4yr old child. She wants him back even though she didnt do anything wrong. The thing is... he made a move on me which I rejected and I still havnt told my mum cause it will upset her. Ive told my gran and she told me not to tell my mum as I have to think about my little sisters life as well. What should I do? Tell my mum and hope she gets over him, or wait for her to get back together with the creep and live with this secret for the sake of my little sister.