On Monday in the County Court, the family's fractures were plain to see when that teenage boy – now a man in his 40s who has endured years of emotional pain, drug abuse and a sense of worthlessness – challenged his father and stepmother as he read his victim impact statement. "This offending has had a huge effect on my life. I don't trust anyone," he began, before turning around to his father and stepmother, the latter in the dock, and repeating one word. "Anyone." Instructed to face the front by the judge, the man apologised to the court. "Sorry, I just felt like I had to let him know." From there, the man tearfully recalled his inability to connect with family members and life as his family's "emotional punching bag". "I learnt that if my own family couldn't treat me with kindness then I shouldn't trust anyone else," he said.

He said he always thought women were conniving and could not be trusted so never had female role models, and was never interested in meeting women, "partly because of having no confidence, but also because I believed there was no point as I would end up getting hurt". The stepmother was in September found guilty of two counts of incest and two of gross indecency, related to a sexual relationship she initiated when the boy was between 13 and 16, which included explicit instructions on sex acts and a threat she would tell his father. Prosecutor Carolyn Burnside said the stepmother – who cannot be named, so not to identify the victim – once sent her other stepchildren to buy fish and chips so she could have sex with the boy at home. "Her crimes have scarred her stepson and others profoundly," Ms Burnside said. The woman denied the offending, the court heard, and still maintained that position. She was found not guilty of seven charges.

The victim on Monday recalled his inability to concentrate at school at the time, which led to him leaving early, and then of using drugs as a coping mechanism. He spoke of social isolation and putting on an angry facade so no one would go near him. Of life on "red alert" always waiting for something bad to happen. And concerns his own children would accept his outlook on the world as normal. "I try to tell myself to man up and build a bridge and get over it, but it is not that easy," he said. His biological mother was also in court – seated two rows in front – and explained the impact of not knowing why her son went from a happy and outgoing child to an unsure and uninterested adolescent and man. She suspected at the time it was the divorce, and so often questioned her abilities as a mother.

"You took my son's trust and innocence and in doing so you took the innocence of our family," she said, directing her words to the stepmother. "Unfortunately the blame was deflected onto him by you and your husband and the emotional damage already done was compounded by this, which set my son on a path of self-destruction and self-loathing, that the family have walked together with him for more than 30 years." She admitted to a strained relationship with her son after years of "worry, stress and anguish on a near daily basis" and feeling like he blamed her for not protecting him. All she expected was for the stepmother to keep the children safe. "That all comes down to me trusting you to be a good stepmother, a trust you betrayed," the mother said.

The stepmother is to return to court next month, when her lawyer presents arguments in mitigation. She is on bail.