Sexual-related post-traumatic stress symptoms (sexual-related PTSS) refers to the traumatic reactions that are replicated during sexual activity among survivors of child sexual abuse (CSA). However, the construct of sexual-related PTSS have been adapted from clinical work with survivors, and research with limited examination of the scales themselves. Given this gap, the current study offers the development of a new measure (PT-SEX) that examines sexual-related PTSS. The study was conducted online, among two convenience samples of women survivors of CSA (study 1 included 451 women and study 2 included 330 women). Six reliable PT-SEX factors emerged from Study 1: Dissociation during sex, intrusiveness during sex, shame and guilt in regard to sexual aspects, pleasing the other during sex, interpersonal distress, and hypervigilance during sex. Study 2 revealed survivors of CSA had significantly higher sexual-related PTSS levels as compared to participants without such a history. Also, post-traumatic stress disorder and sexual-related PTSS made unique and unshared contributions to the observed data, including sexual self-esteem, sexual motives, relationship satisfaction, compulsive sexual behavior, and mental health. CSA significantly moderated the associations between sexual-related PTSS and sexual self-esteem, sexual motivations of self-affirmation and coping, and depression and anxiety. Findings from the current study show that over time, the trauma of CSA seems to be implicated in survivors’ sexual experience. As sexual difficulties are accompanied by sexual-related PTSS, these symptoms are unlikely to resolve by trauma-focused therapy and must be actively targeted in therapy.