Andrew File, 42, of Sleaford, caused the death of Murielle Vaillant, 57, from Quebec, by driving carelessly  on the A701 near Tweedsmuir in May 2012.
His car veered onto the wrong side of the road and hit a hire car driven by Mrs Vaillant's husband, Louis.
Judge Lady Rae told File he had left a family in "deep mourning".
The High Court in Glasgow heard how he had been travelling to Scotland in a Dodge Caliber when the crash took place.
Mr Vaillant, a businessman who lives near Ottawa, was driving south with his wife of 35 years after a visit to St Andrews.
In evidence he said File's car struck his car without warning.
He said he immediately noticed his wife was dead and added: "I touched her face and she was gone."
The crash caused Mr Vaillant's car to leave the road, and it ended up on the verge.
Mrs Vaillant died at the scene.
Her husband then telephoned their son in Canada to tell him what had happened.
He added: "I said to him 'I just had an accident. Your mother's gone.'"
Police officers discovered that File had been driving at speeds of more than 90mph earlier in the day on the motorway between England and Scotland by checking his sat-nav.
They also found that once he drove onto the A701, he was travelling at speeds of more than 70mph.
Defence QC Derek Ogg told the court: "Mr File has no memory of the lead-up to the accident.
"He is devastated and haunted by the accident and has suffered depression and has considered suicide."
He was convicted of causing death by careless driving after a week-long trial.
File had originally faced a charge of causing death by dangerous driving, but a jury convicted him of the lesser charge.
Lady Rae told him: "You have left a family in deep mourning for a mother and wife all because of your irresponsible driving.
"You were driving in excess of the speed limit for some time prior to the crash.
"You went into the opposite carriageway and Mr Vaillant's car left the road and ended up on the verge with his wife dead beside him."
In addition to jailing him, she also banned File from driving for five years.
A Lincolnshire man who denied killing a Canadian tourist in a crash in the Scottish Borders has been jailed for three years.