Cameron John Pearson, 44, struck Alice McShera, 34, in the head and face with the bottle between five and nine times in a lethal late-night attack at the Crown Towers complex in Perth on October 30, 2023.
Pearson pleaded guilty to murdering Ms McShera and was sentenced on Tuesday in the WA Supreme Court to life in prison.
He will be eligible for parole after serving 19 years.
"Your offending involved a brutal, senseless and unprovoked attack," Justice Michael Gething said.
"You abused her trust and exploited her vulnerability.
"Ms McShera was an entirely innocent victim."
The family law specialist, who had previously helped the killer with legal matters, suffered multiple injuries, including skull fractures, deep lacerations to her head and face, a brain bleed and traumatic brain injury.
Hotel staff found her body on the bathroom floor the following day with the bloodied bottle beside her.
Pearson was in a bathtub in the same hotel room - number 1227 - in his underwear, holding a broken champagne glass with serious self-inflicted injuries.
He later told police the pair had been arguing after Ms McShera told him she was leaving him and he attacked her while she was putting on makeup and getting ready to go out.
"I lost it and hit her over the head," he later told investigators during an interview.
"Because she was leaving me.
"I killed the person I love."
The courtroom, packed with members of the Perth legal fraternity, heard the pair had been staying at the hotel in a bid to reconcile their increasingly volatile relationship, which involved recreational methamphetamine abuse.
After Pearson, an unemployed fly-in-fly-out boilermaker, killed Ms McShera, he covered her with towels and a robe and "chilled out" in the hotel room.
He had intended to ask Ms McShera for her hand in marriage, but had learned she did not love him, Justice Gething said.
Ms McShera was described to the court as kind and generous and passionate about the prevention of violence against women and children.
She and Pearson, a father of one, had used methamphetamine and drunk alcohol before the deadly assault.
Pearson attempted to end his life after hotel staff tried to enter the room, following a call from Ms McShera's concerned family.
"Your offending involved the most extreme kind of domestic violence," Justice Gething said.
Ms McShera's former employer, Murray Chambers, said she was a much-loved colleague and fearless barrister with a very promising future.
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