Curtis Haas was convicted of manslaughter last year in the 2007 death of Wendy Henry.
A judge ruled last May that Haas gave Henry 16 high-potency morphine pills when he knew the dosage could kill her.
He also didn’t call 911 for two days, even though she was showing obvious signs of having overdosed.
The Crown had been seeking a five-year sentence, in part because Haas had no prior criminal record and may only have a few years to live due to poor health.
The defence wanted a conditional sentence which would have allowed him to remain free in the community.
The case has dragged through the justice system for years because of an extensive police investigation and the questions about Haas's health.
Haas originally told police Henry wanted the morphine from him to "get high.'' He later changed his story, saying she needed it to deal with chronic pain. He also told a different version to a security guard in his building, claiming Henry had "gotten into'' his stash.
Haas denied any wrongdoing. His lawyer argued Henry was responsible for her own demise because she willingly ingested the pills.
Haas told the judge at a sentencing hearing in December that he's sorry for what happened.
"I have never forgotten that day. And it is still very apparent in my thoughts every day.''
(CJOB, The Canadian Press)