He left behind Ms Gillette and their two sons, Ethan, then four, and Charlie, two. The last thing she heard after their argument was the front door opening and the sound of his car reversing down the drive.
Since then there have been public appeals and police searches. He was listed as an official missing person and there was no sign of him - until one day last summer when an extraordinary chance encounter meant they were once again face-to-face.
"I always sort of believed he was out there somewhere. But it was a bit of a shock seeing him. I don't know how to explain it - it was numbing," Ms Gillette told news.com.au.
He was only close by for a few moments and Ms Gillette spent them furiously trying to decide if the stranger standing almost within touching distance was her long-lost partner.
"In my head there was this argument. Is it? Isn't it? But it definitely was him."
The 44-year-old was with her eldest son Ethan, now 15, and a daughter she had from another relationship.
It was on January 27 at Caloundra Stockland shopping centre on the Sunshine Coast where the remarkable encounter occurred. Ms Gillette, along with her son and daughter, were walking out of the shopping centre and along the footpath, while the man she believes is Mr Jenkins was coming right towards her.
She said to Ethan, "that's Russell over there" but the teenager initially didn't believe her.
"He shrugged it off at first but then he started observing him closer and then when we got home he checked him out on the internet."
The only photo the family has of Mr Jenkins is the one that features on his missing persons page, which is now almost 15 years old. All the others of him were lost during the Queensland floods in 2011.
"Once he checked the picture he realised it was him as well. He's older, obviously, more heavy-set, but I'm positive it was him."
The man who turned her life - and those of her children - upside down when he abruptly walked out on them was now "less than a car length away" from her.
"We were very close and we kept watching each other walk past. And yeah, whether he was realising that was us, just as he were realising that was him, it was dumbfounding. We weren't even a car length apart and we just bypassed each other staring."
When Ms Gillette and her children got into their car she kept watching. And he was watching them.
"He was very observant of us. By that time he had taken off his sunglasses and I realised that was definitely Russell."
Even as they drove away the man kept watching them. She told news.com.au she now wishes she had said something.
"But at the same time I don't really know what to say. It's been a long time and obviously people's lives change. Whether he lives there or was just passing through, I'm just positive it was him."
She said: "I don't know if it is the awkwardness of the situation ... He could have approached us too, but what do you say to someone who has been missing for over 10 years?"
Over the past decade, she has played over and over in her mind what she would say and do if she ever laid eyes on him again. She expected it would be in their home state of Victoria, not 1800kms away on the Sunshine Coast.
"I'd never thought I'd see him close up anywhere else, especially after so long. It was just such a shock."
The main reason she decided to go public with another appeal is for their two sons. Over the past decade she had to make a "conscious effort" to put it behind her so she was able to get on with her life.
But a near-death experience three years ago in a serious car crash changed things.
"I was lucky to survive that. And if I hadn't have lived then my boys wouldn't have any parents. Maybe that's why I'm doing it. Because, God-forbid, but if something happens to me maybe he will show his face and be a parent."
But it was her sons who encouraged her to go to the police and report the sighting.
What Ms Gillette wants him to do is go to a police station and tell them he is OK. From there though she was unsure about what would happen.
"Me, personally, I don't expect Russell would come back into the picture. But that doesn't mean his sons can't know him."
They had asked about him many time over the years, especially Ethan as he was getting older. "There is always this not knowing - there is a gap there that needs to be filled in."
For her, there is no longer any anger.
"I think I have moved past all of it. There was a lot of emotion there, but I had to move past it. For my own wellbeing and that of my boys."
