Overwhelmed by grief, she had since been struggling to care for their four children while trying to keep their business afloat.
"Cecile, you took my soulmate from me ... You killed me also."
Riviere, 27, a French national who has been living in New Zealand on a working visa for the past two years, was appearing for sentencing by Judge John Brandts-Giesen on an admitted charge of careless driving causing Saunders' death on State Highway6, at Nevis Bluff, on December 20.
The court heard how Riviere, who had a female passenger, steered across double yellow lines in a no-stopping zone with the intention of pulling into a gravel layby overlooking the Kawarau River.
The van collided with a ute driven by Mr Saunders (39), which crashed about 100m down a steep bank and ended partly submerged in the river.
He had been on the correct side of the road and driving within the speed limit at the time of the collision.
He and his wife, whose children are aged 7 to 16, own Central Wilding Tree Control Ltd.
The last of several family members to read out victim impact statements in court, Saunders told Riviere she did feel compassion for her.
"I am empathetic that you feel pain. I know part of my journey is to forgive and move forward with my life, but I will never be the same person.
"I cannot forgive you today."
Counsel Tim McKenzie said Riviere was "probably the most upset defendant" he had represented in his career.
She had been prepared to meet the victim's family under the restorative justice process, but accepted they had chosen not to participate.
"Cecile wants the family to know she is thinking about them a lot."
The defendant had been careless in failing to check the road ahead was clear, McKenzie said.
However, the meaning of the no-stopping sign she had driven past as she approached Nevis Bluff was an "anomaly".
It appeared to be about rockfall risk, rather than stopping for general reasons, particularly given the presence of two laybys on the other side of the road. Judge Brandts-Giesen said driving mistakes due to carelessness did not usually lead to such tragic consequences.
There had been no exacerbating features such as excess speed, alcohol, or fatigue.
"There was nothing to suggest that until milliseconds before this accident, she was driving dangerously or carelessly."
However, the crash was not a freak occurrence, but caused by factors over which the defendant could control.
She had probably been distracted by her passenger asking her to stop so she could look at a kayaking rapid below.
"But the driver is the captain of her car, and must take responsibility for how it's driven."
In sentencing, he took into account her remorse, good character, willingness to engage in restorative justice, and offer to pay reparation.
He also recognised she had suffered "physical and psychological trauma", and was isolated from her family.
He arrived at an end sentence of just over eight months' prison, which he converted to four months' home detention.
Riviere must pay reparation of $12,500 to the Saunders family, is disqualified from driving for 13 months, and must complete a driving improvement course.