Insurance broker Alan Bennett, 56, of Cove, was lured to his death with the promise of sex from prostitute Julie Carroll, 25, who coaxed him to enter a lane with her in Aberdeen last May.
Her lover Paul Balgowan then put a knife to Mr Bennett's throat and demanded the 100 he was about to hand over to Carroll for sex.
The pair had planned to rob Mr Bennett to feed their heroin habit, but when Mr Bennett fought back, Balgowan, 24, stabbed him six times and he bled to death.
Yesterday judge Lord Matthews jailed Balgowan for 13 years and also ordered him to be monitored in the community for two years after his release.
Carroll was jailed for six years and 11 months and ordered to be monitored in the community for two years after her release.
Carroll admitted killing Mr Bennett and Balgowan was found guilty of his culpable homicide after trial. Both were originally charged with murder.