The victim of the blackmail told the court she met the defendant through work at the start of 2020.
"I felt Jayden understood me and was patient with me," she said.
The exchange of explicit photos was his idea, and the woman said she never foresaw they would be used against her.
When the victim discovered Haggerty was married with a third child on the way she withdrew and cut ties on some social-media platforms, something that angered him and prompted a series of threats as he sought to re-establish contact.
"You shouldn't have crossed me ... I've got nothing to lose," the defendant said.
The victim told the court she struggled to sleep, stopped eating and was too scared to leave the house alone.
"Jayden became unrecognisable to me. He wanted something and didn't care about me at all. It was all about him and how it affected him," the victim told the court.
"Having to deal with all this nearly pushed me over the edge ... I've never been so scared of someone in my life."
Before sentencing was adjourned today, defence counsel Len Andersen QC said the convictions had seen his client lose his "dream job" as an airport firefighter.
He was now working in the manufacturing sector.
Andersen said the defendant needed significant help, pointing to his mental health issues.
Hearing about that, the victim said, was "a kick in the guts".
She hoped her own psychological battle would not be overlooked.
"Jayden's mental health issues came from him being cornered after being found out to be a liar and a cheat," the woman said.
"I suffer every day because of him."
Judge Phillips apologised to the victim for postponing sentencing but said a fair outcome could only be reached if all appropriate evidence was in front of him.
Haggerty will be sentenced in January.