Colin Howell and Hazel Stewart appeared in Coleraine court
Dentist Colin Howell and his ex-lover Hazel Stewart stood in the dock together for the first time charged with the murders of their partners.
North Antrim Magistrates' Court was told a delayed preliminary inquiry should now go ahead on 12 April.
Mr Howell, 51, formerly of Glebe Road, Castlerock, and Mrs Stewart, 47, of Ballystrone Road, Coleraine are jointly charged with murdering their spouses.
Their bodies were found in a fume filled car in Castlerock in May 1991.
A coroner originally ruled that Lesley Howell and RUC constable Trevor Buchanan had taken their own lives, but the case was reopened last year after new information was given to the police.
Mr Howell is also charged with drugging and indecently assaulting women patients at his clinic on separate dates over a 10-year period dating back to March 1998.
It was the first time that the two accused had sat in the dock together, separated by a prison officer.
Mr Howell who was wearing jeans, a white t-shirt and a grey sports top, appeared to pray and then stared straight ahead.
Mrs Stewart who wore a blue raincoat and black trousers, bowed her head and closed her eyes as her solicitor confirmed the change of date.
A district judge at the Coleraine court agreed to the latest delay but warned that he wanted the matter "moved forward".
Mr Howell was remanded in custody while Mrs Stewart was released on continuing bail until next month's hearing.