Mother started having sex with her son, 12, when he came into her bed because he was sick - and made him feel 'important and special' as he was hitting puberty

Children's teenage years are supposed to be full of learning and laughter but one man has spoken of the unimaginable abuse he received at the hands of the person he trusted most - his mother.

'Hamish' who is now in his 50s, was 12 years old when his childhood innocence was taken away from him by his mum.

The woman who he described as 'mentally unwell' had sex with him one day when he was recovering from sickness.

She had this big bedroom and if we were ever sick or anything like that we'd stay in her bed. One day she just initiated it, she just started touching me and it just went from there,' Hamish told news.com.au.

'She preyed on the fact I was coming into puberty and made me feel important and special.'

Hamish thought he had it all growing up, he lived in a wealthy suburb and went to a private school but all that meant nothing behind closed doors.

He suffered physical and mental abuse that has scarred him for life and was warned to not talk about the sexual abuse saying that he was told that 'people wouldn't understand'.

Hamish said that the abuse only stopped once his mother died when he was 15 but he has carried the scars of those awful three years for a lifetime.

The memories of his traumatic childhood were repressed and Hamish moved on and fell in love and got married in the early 90s.

He struggled with the abuse and kept it secret from his wife for 20 years until a story surfaced in the news that brought memories flooding back.

'It's really hard to tell someone you love, "By the way, my mother abused me and I had sex with my mother",' he said.

Unfortunately for Hamish the secret took its toll on his relationship and he and his wife split three years ago after he had an affair.