The Maine Supreme Judicial Court upheld on Tuesday the conviction of 35-year-old Luc Tieman.
A Somerset County jury found Tieman guilty last year.
Authorities said Valerie Tieman died from gunshot wounds to her neck and head.
According to testimony at the trial, she was found with a bottle of cologne, a potato chip bag and love notes in a shallow grave on wooded property owned by Luc Tieman's parents.
In their decision, the justices said the judge who heard the case was correct when he admitted Facebook messages into evidence and there was ample evidence for a jury to convict Luc Tieman of murder.