"I was a product of my environment. I became pretty much a drug addict around 9 or 10, I was getting kicked out of school ... The crime started not long after."
By the age of 15 Ben was locked up for manslaughter.
After his release four years later, Ben and Nikki began a relationship.
"We moved in together and soon after, that's when the violence began," Nikki said.
"I thought if I loved him enough that would outweigh the bad.
"It started on a spiral of ugliness. Constant police call outs, living in fear. There was never a time where I had any control. It was like living a nightmare."
But when the police were called Nikki wouldn't speak.
"I didn't really want anyone to know, I just wanted help."
The couple talked to counsellors, Nikki researched the situation, they both wanted help and Ben going to prison wasn't the answer, she said.
They got married but the violence didn't stop.
Then a police officer told Ben about Man Up; A programme designed to help men understand and overcome dysfunctions. For Ben it was domestic violence, for others in the programme it's addiction, anger or depression.
Nikki noticed the difference immediately.
"The drug use stopped almost instantly. Then the violence stopped. I remember getting to one day without violence, two days, three days, a week, a month."
Ben had done more than 60 programmes before Man Up but this was different.
"It was with men who had gone through the same things. Walked the same path and I was able to relate to them."
"I felt comfortable to talk about the domestic violence, my upbringing, because they were talking about it themselves."
Nikki joined the sister programme Legacy. Now the couple facilitate the programmes.
"The life changes that we had, we want to give it to others because we know it works," Ben said
"I see it in my own life. I look in the mirror and I'm happy with the man I see. Before I was disgusted, disappointed. Now I can look in the mirror and say 'I've been through that now I'm able to help others that are going through it'."
For others in the situation the Puruas were once in, Nikki said "if you're not happy you have to do something to change it".
"It's about taking the stand for your family. It's hard to say 'hey I need help'.
"It's breaking the cycle ... we didn't want our kids to go through that."
Ben and Nikki have shared their story in the lead up to White Ribbon Day tomorrow, the International Day for the Elimination of Men's Violence Towards Women.
As part of the campaign, three groups have been riding across the South Island, Lower North Island and Upper North Island.
One of the rides culminates in Rotorua tomorrow. Aaron Morrison, who leads the ride, said while there wasn't anything formal planned for the day, the ride raised awareness of the cause.
"We've got to step up and be respectful and look after our partners, our mums, wives, daughters and granddaughters."
White Ribbon campaign manager Rob McCann said the campaign aimed to promote respectful relationships.
"What we're trying to do is we're asking men to stand up the focus is on those men who don't use violence.
"We've got this incredibly sad epidemic occurring and we are not going to change this if people say 'I'm not violent, it's not going to affect me, it's not my problem'."
McCann said the campaign also focused on the way young men were raised.
"We're not willing to have conversations with our young men about what respectful relationships looks like."
Rotorua area commander, Inspector Anaru Pewhairangi, said police spent a "significant amount of time" investigating family harm incidents.
Pewhairangi said the increase in investigations could be due to increased family harm campaigning nationally and in the community.
He said Rotorua Police supported White Ribbon Day and encouraged people to report family violence.
"It's not a private matter – it's a crime. People in violent relationships often cannot help themselves. They need your help.
"We need to ensure that people who are in difficult situations recognise that there is hope. With hope, we can help. Please call us so we can work together."
Where to get help
If you're in danger now: • Phone the police on 111 or ask neighbours of friends to ring for you. • Run outside and head for where there are other people. • Scream for help so that your neighbours can hear you. • Take the children with you. • Don't stop to get anything else. • If you are being abused, remember it's not your fault. Violence is never okay
Where to go for help or more information: • Shine, free national helpline 9am- 11pm every day - 0508 744 633 www.2shine.org.nz • Women's Refuge: Free national crisis line operates 24/7 - 0800 refuge or 0800 733 843 www.womensrefuge.org.nz • Shakti: Providing specialist cultural services for African, Asian and middle eastern women and their children. Crisis line 24/7 0800 742 584 • It's Not Ok: Information line 0800 456 450 www.areyouok.org.nz