Donna McMurchie, 40, said catching her husband's killer would bring the family some comfort.
And she revealed it was only a twist of fate which led her partner of more than 20 years to go out on the night he died.
John McMurchie, 50, was found seriously injured in Dundee's Fintry Terrace in the early hours of August 12 last year.
The father-of-five and grandfather-of-two, from Errol, Perthshire, was taken to Ninewells Hospital in the city, where he was confirmed dead on arrival.
Police probing his murder have said he was involved in a "significant physical altercation" at a house in Murrayfield Gardens shortly before he was discovered.
No-one has been charged in connection with Mr McMurchie's death.
Mrs McMurchie has revealed her husband only went out that night after discovering he had got his shifts mixed up at the Dundee garage where he worked as a security guard.
She said: "John had been so happy when he found out he wasn't working. I'd been dropping him off and he turned to me and said he could go out instead. I so wish he'd just gone to work."
She urged anyone with information about that night to contact police.