The love between Paul Rossington and Kristen Schroder was most obvious in their final moments.
The couple, who had been together for about nine months, had taken a cruise on the Carnival Spirit in the hopes of strengthening their sometimes volatile relationship.
At 8.48pm on May 8, 2013, Ms Schroder climbed onto the balcony of cabin 5281, lost her footing and fell overboard. Mr Rossington, a paramedic, jumped in after her, from a height of 18 metres in an attempt to save his girlfriend's life.
The couple's bodies were never found.
"The premature deaths of young people are always heart-rending and distressing," deputy state coroner Hugh Dillon said on Tuesday.
"The deaths of Kristen and Paul are even more distressing than most because of the loneliness of their deaths in a dark ocean, and because they had gone on the cruise in the hope of restoring and reinforcing their relationship.
"Paradoxically, what they had struggled to achieve in life – loving unity – they perhaps managed in their last actions alive."
Mr Dillon said it appeared that Ms Schroder, 26, was making a "dramatic gesture to alarm and test" Mr Rossington, 30, when she climbed up on the balcony.
Earlier that evening, CCTV cameras captured the couple having a "terse" conversation while playing a poker machine in the ship's casino, and they returned separately to their cabin.
The couple, who lived in Barraba, near Tamworth, had a history of fighting, breaking up, and reconciling, but there was nothing to suggest Ms Schroder was threatened by Mr Rossington that night, or that she wanted to end her life, Mr Dillon said.
Both were dealing with the aftermath of divorce, and Ms Schroder was seeing a psychologist for anxiety and depression.
In her final months, Ms Schroder wrote that her anxiety was spiralling out of control and she was treating her boyfriend harshly.
"I'm really worried I'm losing control and hate that I am lashing out at the person I care about most in the world and has been the biggest support I could have imagined," her diary entry read.
"I don't like who I am or how I'm treating him and I need to figure it out."
Mr Dillon said Ms Schroder's feelings made the deaths even more tragic.
"She had the insight to recognise this, the will to do something to improve her mental state, resilience, and a desire to heal her deteriorating relationship with Paul," Mr Dillon said.
"But her death deprived her of the time to develop that relationship into a more stable and harmonious one."
Mr Dillon proposed nominating Mr Rossington for an Australian Bravery Award, because he acted courageously in jumping after his girlfriend, knowing he was in danger.
The coroner also recommended Carnival Cruises include "man overboard" safety procedures in their verbal briefing to passengers, but added there was no suggestion of failure on their part to prevent the deaths.
Outside the NSW Coroner's Court, Ms Schroder's family did not speak to reporters.
Mr Rossington's parents, Christeen and Richard, surrounded by their children Justin, Trent and Lisa, said they were pleased with the findings.
The young men wore Mrs Rossington's family tartan kilts in a tribute.
"He would have been humbled," Mrs Rossington said of her son's nomination for the bravery award.
"He was a very, very quiet man. He would not want all this publicity."
