Ahsan Hassan, of Dashwood Avenue, High Wycombe, murdered Zofia Sadowska in a disused kebab shop on 18 September.
Reading Crown Court heard Hassan convinced the taxi driver she was drunk and asleep and later told police the death was part of a suicide pact.
The 28-year-old, who denied murder, will be sentenced on 10 April.
Usman Ansar, 30, also of Dashwood Avenue, High Wycombe, was found not guilty of perverting the course of justice.
Hassan took Ms Sadowska to the disused kebab shop on Gayhurst Road in High Wycombe at about 23:30 BST. A post-mortem found the cause of her death was asphyxiation.
At about 02:00 BST, he put her body into a taxi and they were driven to his home in Dashwood Avenue.
Police and paramedics were called to the property just after 05:00 BST, to reports of an attempted suicide.
Det Insp Stuart Blaik, of Thames Valley Police, said Hassan had tried to cover up the crime by claiming her "evilly planned" murder was part of a suicide pact.
He said: "Hassan was deeply controlling, manipulative and consumed with jealousy."
He added that Hassan's refusal to admit the murder had made it even more of a terrible ordeal for Ms Sadowska's family.
A "deeply controlling, manipulative" man who killed a 20-year-old woman before taking her body home in a taxi has been found guilty of murder.