The jury heard Bowen was possessive, controlling and manipulative
A judge has told a 42-year-old man who murdered his stepson by stabbing him 18 times as he slept he will serve at least 16 years behind bars.
Sentencing Carl Wayne Bowen of Llanelli to life in prison at Swansea Crown Court Mr Justice Nigel Davies said he was a "highly dangerous" man.
A jury had found him guilty of killing promising jockey Jamie Yeates, 15.
He was also convicted of the attempted murder of his wife Maria and wounding Jamie's sister Kimberly with intent.
The jury dismissed his defence of diminished responsibility.
Bowen received a mandatory life sentence for the murder of Jamie but the judge was required to set the minimum number of years he would stay in prison before being released on licence.
Mr Justice Davies said that, as a psychiatrist had decided Bowen was both highly dangerous and that "the prognosis is dire," he should not assume he would be released after the 16 years.
"You will be released only when the authorities have decided you are no longer a danger," he added.
At Wednesday's sentencing hearing, Bowen's barrister Peter Rouch QC, told the judge he could not think of any mitigation he could put forward on his client's behalf.
Mr Justice Davis said Bowen had been so "manipulative and controlling" he had even tried to trick psychiatrists by researching the definition of diminished responsibility put forward as his defence.
"You told a psychiatrist, who asked you why you had stabbed Jamie, 'it is not me.' You were trying to say it was not you, or your character," said Mr Justice Davies.
"It seems to me you have a very distorted view of what you are really like. It was you. It was not out of character.
"You are highly dangerous and you are not suffering from a psychotic illness. One psychiatrist said the prognosis was dire. You are a dangerous man and I'm not sure you realise that."
Mr Justice Davis said that while the violence had not been planned at length Bowen had been having evil thoughts "for some time."
He said that, for example, he had once told Maria that if she ever left him he would kill her "and plead diminished responsibility."
Bowen, he added, had taken a keen interest in killings and murder and had worked himself up into a state.
"Why you selected Jamie as your victim is known only to you, but it may have been a way of getting back at your wife.
"You did not love Jamie - but she did.
"This was a very, very cruel crime, all born out of your pathologically jealous state of mind," he added.
Bowen showed no reaction as sentence was passed.