Derek Plourde of Fort Macleod was originally charged with second-degree murder in the September 2009 death of George English at a Crowsnest Pass cabin.
Last May, he was convicted of manslaughter and was sentenced to five years behind bars.
But Plourde appealed on nine grounds, citing alleged errors of law, failure to consider relevant evidence and actions he took in defending himself.
Court heard Plourde was suspicious that his wife was having an affair with English, found them at the cabin and three fights occurred, one leading to the stabbing.
Plourde argued English came after him with an axe, but the three-judge panel disagreed with all nine grounds and dismissed the appeal.
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