For many survivors of sexual violence, the thought of seeing their attacker again can be very distressing. But authors Thordis Elva and Tom Stranger are sharing their story – in a candid, emotional and sometimes angry conversation – of how facing their past help lead to forgiveness.

First addressed in a TED Talk last year called "Our Story of Rape and Reconciliation," this month they're releasing their book, "South of Forgiveness," which chronicles their troubled history.

Tom Stranger (left) and Thordis Elva CBS News

"What I did that night was – it was a hugely self-absorbed and hurtful act. It was nothing other than rape," Stranger told CBS News correspondent Charlie D'Agata.

While Stranger may have lived in self-denial for years, he came to that realization when finally confronted by his victim, Elva. In 1996, she was only 16 years old. He was an 18-year-old exchange student from Australia, visiting Elva's native Iceland.

They shared what he described as a "lovely teenage romance" for about a month when they went to the school's Christmas Dance where Elva got very drunk.

"I was gone. I couldn't move a limb or utter a word. But to my gratitude, Tom came to my rescue in that situation and got me outta there and took me home," Elva said. "But that gratitude and relief turned to horror and betrayal when we came home and he proceeded to undress me and have his way with me."

More than 20 years have not erased the vivid memories of every last second of that brutal assault.

"My head was facing the alarm clock, which glowed in the dark, so I silently counted seconds for the duration of it, and that's how I know how long it lasted. And then I got up to 7,200 seconds," Elva said.

That's two hours, to be precise.

"There was a sense that I had a right to sex, and of course, it wasn't sex," Stranger said.

They broke up soon after. Elva told no one. Never even thought to go to the police.

"I didn't realize right away what it was. It took me a long time to put into context that this had indeed been rape. Because I had misconceptions. I was a 16-year-old girl that thought that perpetrators were armed, masked lunatics that lurk in a bush and jump at you. I didn't think it could be your boyfriend, that it could happen in your own bed," Elva said.

She said she felt "broken" in the years that followed. In the confusion, denial and shame of those years, they even spent a short time together in 2000, but neither was able to confront their past.

In 2005, on the verge of a nervous breakdown, Elva e-mailed Stranger, nine years after the assault, to burden him with the pain he alone caused her. She figured he'd deny it, or call her a liar.

"The only thing I didn't prepare for was Tom's confession. He wrote back, unwaveringly owning up to his actions," Elva said.

After a lengthy correspondence they agreed to meet in person. But they now lived on opposite sides of the planet.

"We met in Cape Town in 2013, 16 years after that fateful night…because it was middle ground, literally," Elva said.

The tumultuous days that followed in South Africa would come to form the heart of their book, "South of Forgiveness," an unlikely and uncomfortable memoir. Stranger said his contribution simply came from the perspective of a very normal teenager who caused a lot of pain and a lot of hurt. He took part because he feels a responsibility to educate men who find themselves in similar situations that what he did was wrong.

"Far too often the responsibility is attributed to female survivors of sexual violence and not to the males who enact it," Stranger said in his TED Talk.

There are those that feel that the attackers voice should not be heard as loudly as that of the victims – or at all.

"I understand that. I understand having me here, sitting in this chair is a difficult thing for people to see and to hear me and to listen to me," Stranger said.

But listen to him they must, said Elva, because if more men understood that any sex without consent is assault, there wouldn't be so many victims.

"We tend to scrutinize the wrong person. We tend to pour over the details of survivors and question, 'What was she wearing or drinking or thinking?' As opposed to asking, 'What was the person responsible for the violence thinking?'" Elva said.

Elva said together they have a duty to help fight that violence and that she has a right to heal.

Stranger was never prosecuted, partly because it took so long for Elva herself to realize she was the victim of a crime. By then the statute of limitations had passed and Stranger was half a world away.

The reaction to their TED Talk has been positive, for the most part.

Stranger will not profit from the book. His share of the proceeds go to a shelter for sexual assault victims in Iceland.