In October 2011, a seemingly content Jouni Risto Ahola phoned a friend and asked her to be a bridesmaid in his forthcoming wedding.
Then he walked home and beat his bride-to-be, Sandra Margaret Thomson, to death with a wooden baton in an "extended, merciless and excruciating" attack.
Ahola, 52, was jailed for at least 18 years in the Supreme Court at Wollongong on Friday.
Justice Richard Button said it may never be known what sparked Ahola's ferocious and frenzied attack on his fiancee as she prepared dinner in their home near Batemans Bay.
"It may be that an argument about a trivial matter escalated," Justice Button said.
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"Perhaps the subject matter was as banal as the meal that was about to be served."
What occurred next was inexplicable.
Ahola took a wooden baton Ms Thomson kept for her own protection and beat her around the head a number of times.
Ms Thomson tried but failed to escape into the yard during the beating.
At one point, the attack stopped and Ms Thomson either crawled or was carried into the bathroom by Ahola.
But when she tried to close the bathroom door on him, he started beating her again.
The "ferocity of the attack" was evident from blood spatters that reached the ceiling and by Ms Thomson's wounds, Justice Button said.
Overall, she suffered 19 separate injuries including a fractured skull.
Eventually, Ahola regained his composure and attempted to resuscitate Ms Thomson.
When this failed, he "callously smoked a cigarette over (her) and permitted ash to fall on to her body as he pondered what to do", Justice Button said.
Ahola later told police he had found his fiancee brutally murdered by an unknown assailant.
He was eventually charged with murder and found guilty by a jury in May this year.
Despite everything appearing "rosy" on the surface, Ahola and Ms Thomson's relationship was not as good as it appeared, the court heard.
Ms Thomson had become a heavy drinker in middle age and Ahola "shared her commitment to alcohol", Justice Button said.
Although Ahola was affected by alcohol on the night of the murder, he was not "unusually or unexpectedly intoxicated" when he attacked Ms Thomson, Justice Button said.
"The final ordeal of the deceased was extended, merciless and excruciating," the judge said, setting a maximum sentence of 24 years.
"Ultimately she was left to die on the bathroom tiles."
Taking into account time spent in custody, Ahola will be eligible for parole in October 2029.
