David Crapper, 38, has been sentenced to 17 years imprisonment, with an extended four years on licence.
His wife Kim Crapper, 39, has been sentenced to six years imprisonment, with an extended licence of three years.
The offences came to light when the victim, who is not named for legal reasons, told a friend about their behaviour and they were arrested.
The defendants pleaded guilty to sexual assault of a child under 13, sexual assault, cause/incite a child to engage in sexual activity, and engaging in sexual activity in the presence of a child. David Crapper also pleaded guilty to rape and causing a child to watch a sexual act.
They were sentenced at Cardiff Crown Court on Friday (November 18).
The court heard the abuse began when the girl was very young and was carried out over several years.
Detective Inspector Christine Edmunds, from South Wales Police, said:
“Firstly I would like to acknowledge the bravery of the victim in coming forward.
“We take all reports of sexual assault seriously and urge victims to come forward to report it, regardless of when it happened, safe in the knowledge that they will be treated with respect and dignity and that their allegation will be fully investigated.
“The sentencing judge said it was hard to think of a more monstrous offence and neither of the defendants have shown any true remorse.
“We were determined to get justice for the victim and worked closely with the Crown Prosecution Service to achieve that aim.
“Help and support is available for all victims of sexual violence, and we encourage any victims to come forward.”
Sexual assaults or abuse can be reported to police or to Crimestoppers anonymously on 0800 555 111.
