how to deal with an abusive relationship

i was with a guy for two years and for the whole relationship he was toxic. physically and verbally abusing me, manipulating me and controlling me. we’ve been broken up for a year now but every now and again i can’t cope with what he done. i’m 18 now and i want to tell my mother but i know she’ll bring it to the police and i feel like he will deny it all and it will get no where. does anyone know what i can to help myself