She thought her husband was having an affair. What Leah Mouatt found was worse than she could've imagined.

“How could I be with someone for so long and not know?”

When their marriage of six years began to change, Sydney woman Leah Mouatt began to suspect her husband was having an affair.

The 34-year-old and her 33-year-old husband had been happy in the initial stages of their relationship but he had become distant.

So one night when her husband Phillip John Vellio left their Penrith home to go to the pub, she decided to look online and see if she could prove her suspicions.

Leah Mouatt and her husband, Phillip John Vellio. Via 60 Minutes

She told 60 Minutes that the couple had met online and she thought it was a good place to start to work out what was going on.

Her husband, an IT specialist and car enthusiast, spent many hours online in car communities, so she knew his user names.

But instead of discovering he had been out seeking an affair what she found was much worse.

Leah Mouatt. Via 60 Minutes.

She told The Sydney Morning Herald that hidden far back in the search results on his laptop was a public profile on a pornography website advertised as a "motherless" and "moral free" space for user-generated content – for child pornography.

She found photos of clothed pre-pubescent girls, including a family friend, along with graphic and disturbing sexual comments.

“What he'd written underneath this photo told me what the reality was,” she said.

His favourite porn was "teens" and his sexual preference: "nothing is taboo".

“I knew quite quickly after I saw what I saw that the police had to be called."

She called a friend and together they called the police.

Within hours police seized seven devices. Via 60 Minutes. Within hours seven devices belonging to her partner were seized. They would then find 32,000 images and 854 videos on his laptops, finding many that depicted babies, toddlers and teenagers in various sexual acts

She said, "things happen to these children that we could never dream of - and he was looking at that stuff.”

Her world imploded in July when, Vellio, 33, was convicted of two counts of possessing child abuse material, just one of a growing number of these cases seen by police.

Fairfax Media reports that investigations by the Australian Federal Police jumped by almost 250 per cent in a year to 11,000 in 2015.

Jon Rouse, the head of child pornography Task Force Argos, told 60 Minutes the rise was concerning.

“If you achieve sexual gratification from viewing the image of a child being sexually abused, it cannot be such a quantum leap that you would not take your online sexual fantasies into the real world,” Mr Rouse said.

Phillip John Vellio Via 60 Minutes. While the effect of these abuses on the children is immeasurable there is another, often forgotten victim, women like Leah Mouatt

A world-first study by Melbourne's RMIT University, published last year, found that many partners first found out when police knocked on the door.

"The women were just in so much pain," study author Dr Marg Liddell says.

"Most participants reported mental health issues, with many seeming to experience post-traumatic stress disorder. The fact the pain was still extraordinarily raw years later indicated to me that the system didn't work for them."

For Leah Mouatt the toll was deeper than just the loss of her husband. She told Fairfax Media everything was destroyed.

"I lost my friends, I was taken to [court] by [some members of his family] who didn't want me to get a cent. I lost my home, my car. I've lost my trust in other people. I've had to rebuild a whole life."

Phillip John Vellio and Leigh Mouatt in happier times. Via 60 Minutes. She is now, two years on, rebuilding her life and speaking out in the hopes that women in situations like hers don’t feel as alone.

"What hurts the most is that I went through so much and very, very few people thanked me," she says.

"I did the right thing and I was punished. There was no good that came from it. My life blew apart from that phone call and the only thing that got me through was hanging on to knowing that I'd done the right thing."