Former teacher Mary Kay Letourneau and her student-turned husband, Vili Fualaau, have revealed how their relationship became sexual when he was just 12 years old. On the eve of their 10th wedding anniversary, Letourneau, 53, and Vili Fualaau, 31, spoke about the rape trial and their marriage in an interview with Barbara Walters for '20/20', which will air tonight. The couple, who have two teenage daughters, met when Fualaau was in her second grade class in Seattle. She then taught him again in sixth grade in 1996. Speaking to Walters, Letourneau said they began to spend more time together as she helped him develop his drawing skills that school year and by the summer, their relationship turned sexual. Scroll down for video . Family affair: Mary Kay Letourneau, Vili Fualaau, and their two daughters, Audrey and Georgia, sat down for an interview with Barbara Walters on the eve of the couple's 10-year wedding anniversary . Speaking out: The interview will air on 20/20 on Friday - nearly 20 years after Letourneau's arrest for the relationship with her former student. She was his sixth grade teacher when their affair began . 'The incident was a late night that it didn't stop with a kiss,' Letourneau recounted. 'And I thought that it would and it didn't.' When asked how Letourneau - then a married mother to four young children - felt about the affair, she responded: 'I loved him very much, and I kind of thought, "why can't it ever just be a kiss?"' But it didn't stop there and by the end of the summer, she had fallen pregnant with the boy's child. Months later, her husband discovered a love letter she had written to Fualaau and he contacted police. She was arrested and gave birth to their first daughter while on bail in May 1997. Following a highly-publicized trial, she was sentenced to six months in county jail - although three were suspended - and was ordered to have no contact with the boy. But weeks after her release, she was found having sex with him in her car and fell pregnant with their second daughter. Struggles: The couple said they have had their ups and downs but had a solid relationship to start with . Relationship: The duo first met when Fualaau (pictured in 1998) was in second grade and went on to have a sexual relationship when he was 12 and Letourneau (right in a 1996 school photo) was his teacher . Letourneau gave birth to the second baby girl, Georgia, while she was in jail after being sentenced to an additional seven-and-a-half years behind bars. Being a father at such a young age and bringing up the girls without Letourneau was a struggle, Fualaau said in the interview. He slipped into a depression over the years, he said. 'I don't feel like I had the right support or the right help behind me,' he said. 'From my family, from anyone in general. I mean, my friends couldn't help me because they had no idea what, what it was like to be a parent, I mean, because we were all 14, 15.' He was not allowed to visit Letourneau while she was in prison but he believes contact with her would've helped him. She was the only person he really needed to talk to, he said. 'I mean, if they gave me more options or choices to make instead of just saying, "Oh, you can't talk to her anymore," and I was like, "I really do want to talk to her, though",' he said. In court: She is pictured left in court in 1997 - she ultimately went to prison for seven and a half years - and right proudly showing off her baby bump in a pregnancy photo released in 1998 . Struggles: A teenage Fualaau, pictured in 1998, said he struggled while Letourneau was in prison because he desperately wanted to talk to her, but was not allowed . Reunited: Letourneau is pictured with her daughter Audrey during a prison visit in 2003. In the ABC interview, Fualaau said he struggled with not speaking to Letourneau while she was locked up . 'I'm surprised I'm still alive today. I went through a really dark time.' She was released from jail in August 2004 and Fualaau, who was then 21, asked the court to have the no-contact order overturned, which it was. The couple got married just 10 months later at a Washington winery - when she was 43 and he was 22. They have been together ever since. 'If it wasn't strong enough in the beginning, it wouldn't have carried through those years,' Letourneau told Walters in the interview. The couple remained in the same Seattle community where Letourneau had lived with her first husband and their four children. While she was in prison, her husband had moved the children to Alaska, but she remains close to them, she said, and they have good relationships with their two young sisters. Family: She was married and had four children before the affair. She is pictured, right, with one of her sons . Back together: The couple is pictured during a photo shoot at their Normandy Park, Washington home in 2006. She was released from jail in 2004 and they got married a year later . At home: The couple is pictured with their daughters as they drive near their home near Seattle in 2005 . Fualaau, who is just a year older than his wife's oldest son, said it was 'awkward' for him to be so close in age to his stepchildren. But even though they were happy to be reunited, the couple were not without their struggles. In 2006, Fualaau was back in court - this time in the defendant's chair - for drink driving. He was pulled over for speeding and later found to be over the blood-alcohol limit. In trouble: Fualaau is pictured in court in 2006 for a hearing into a drunken driving charge . He was sentenced to a year in jail with all the time but a day suspended and was put on probation for two years. And last year, Letourneau made headlines after she was booked into Washington's King County Jail for failing to go to court following a 2013 third-degree charge of driving on a suspended license. The couple's two daughters, 17-year-old Audrey and 16-year-old Georgia, also joined them for the interview with Walters. Both girls attend school and sing in a choir in the same district where their mother once taught. Audrey graduates high school in June and will start college next fall, while Georgia is a sophomore. The Fualaau sisters said their parents have told them how they met, but they were not taken aback by the scandalous circumstances surrounding their mom and dad's relationship. 'There was never a sit-down chat, "Now is the time we're going to talk to our children about this",' their mother said. 'They seemed to already know... because they grew up with it.' While some might compare the story to other female teachers in underage sex scandals,  family friend, photographer Mark Greenberg, told the Daily News it couldn't be more different. 'I know there are people out there who find it to be nothing other than this woman broke the law and she's a rapist, and yet there are others who see it as 'love is something that's pure' and here's two people who are enjoying the fruits of that,' he said. Modern family: Mary Kay Letourneau and Vili Fualaau's 17-year-old daughter, Audrey (right), was born while her mother was out on probation. Her 16-year-old sister, Georgia (left), was born behind bars .
Letourneau and Vili Fualaau and their two teenage daughters spoke to Barbara Walters in a 20/20 interview that will air Friday . Letourneau and Fualaau got close as she gave him extra help with his artwork when she was his sixth-grade teacher in 1996 . She said that she thought they would be able to stop at just a kiss but it went much further - and she fell pregnant when he was just 13 . She served a few months in jail and fell pregnant with his second child within weeks; she was then sent back to prison for seven years . But a year after her release in 2004, they married and are still together . Vili Fualaau lamented that he didn't have the right support as a young father of two girls and detailed his history of depression .