Mum-of-three Ms Emers was thrown from the vehicle and died at the scene from severe head injuries.
He said he "felt fine" before Ms Emers grabbed the wheel as he drove her home to Norton.
holds degrees from Parson's School of Design and New York University.
In a trial last month he said he "felt fine" before Ms Emers grabbed the wheel as he drove her home to Norton.
After the verdict, Ms Emers' family said they just wanted justice for her and gained no satisfaction from the prospect of Errington going to prison.
Karen Emers welcomed the sentence outside court, but said: "What I'm upset about is my mam's never got to meet her grandson.
Ms Emers, 37, of Norton, died from severe head injuries after the crash in June last year.
Mr Doswell said the crashed car and Ms Emers, who had not been wearing a seatbelt, were found in a field next to the road.
A post-mortem found Ms Emers had suffered "unsurvivable head injuries".
He admitted setting off to drive Ms Emers home to Norton from his home in Fishburn after drinking a vodka and Red Bull and several cans of cider the previous evening.
Then he said Ms Emers had an "outburst" as the car travelled at 55 to 60mph.
was a passenger in a Peugeot 406 Coupe when it left the road, crossed the central reservation and came to rest in a field.