Married to a double killer serving a 75-year sentence in a Texas jail, Heike Phelan's dream is to one day finally meet her husband outside the prison's walls.

The British woman insists she's "not a lunatic" despite falling in love with William Matthew Schiffert, a man with a disturbing and gruesome history.

So how did a 49-year-old mother-of-two become connected with a double-murderer from the US?

The pair met by chance when Phelan, from Yorkshire, had been writing to a death-row inmate and took part in a Christmas card "swap" organised by a website called Prison Talk.

Advertisement

Schiffert responded to Phelan and the pair became pen pals over the course of a year, exchanging letters back and forth.

After a string of correspondence, Phelan decided to fly to Texas to meet her mystery man for the first time.

The mum-of-two told the Daily Examiner she wasn't a "lunatic" looking for "a guy in prison", but admits her family were strongly against her marrying the tattooed murderer in November 2012.

Schiffert was sentenced to 75 years for being party to the murder of a man fatally stabbed at a motel in Fort Worth in 2001.

But Phelan says her love for Schiffert was strong enough to look past the horror he had committed.

Recalling how the couple's romance began, Phelan said: "My Christmas card went to a friend of my now-husband.

"The friend didn't have time to write back but my husband said 'I've got all the time in the world'. He said as soon as he got the card he knew I was the one."

Four years later the couple got married, but it was met with fierce criticism from Phelan's two adult daughters.

"My family are not happy with me being married to him. It just doesn't get talked about," she said.

"My daughters are 32 and 30 — they don't want to know about him.

"It's my life and it's his life and he has been part of my life for several years. I didn't go out to find a prisoner husband."

She added: "I don't like to give the impression that I'm one of those lunatic women that you see on TV programmes that go out to find a guy in prison. That's not how it happened."

The British mother revealed her lover could apply for parole in as little as two years.

The couple is determined to move in together if he is released, but they face an uphill battle even being allowed in the same country.

Schiffert won't be able to enter the UK due to his convictions while Phelan is barred from the US after overstaying on a tourist visa.

Inspired to put pen to paper, Phelan is writing a book called Child Convict about her husband's troubled life.

"Child Convict is about a young boy born into a world of poverty, abuse and crime. How his upbringing, environment and experiences turned him into a criminal," she wrote on Facebook.

"His experience as a child in an adult prison in the notorious Texas prison system."

The book is set to be released on May 13.