A look back at Mary Kay Letourneau and student-turned-husband Vili Fualaau's relationship

Mary Kay Letourneau was a 34-year-old married mother of four when she began having sex with a 12-year-old former student who she later married. 

The story shocked the nation, as images of the doe-eyed blonde beauty took over television screens and magazines. People wanted to know: How could she?

The answer seemed to be she couldn't stay away. 

Letourneau married Vili Fualaau, now 33, in 2005 after she was released from a more than seven-year prison sentence for having sex with a minor. After a little over 10 years of marriage, Fualaau has filed for separation, according to documents filed in King County Superior Court.

Over the years, Letourneau has sat down with Barbara Walters twice to discuss her relationship with her former student. Here's a look back at some of the shocking details of Letourneau's case and what the couple told Walters after their 10 year anniversary:

Letourneau was Fualaau's second- and sixth-grade teacher

Shortly after her release from prison in 2004, Letourneau told Barbara Walters in an interview that her relationship with Fualaau began as an emotional connection.

"We just bonded, we had similar interests," she said.

Letourneau told Walters she knew Fualaau was interested in her, but she ignored his increasingly aggressive advances. 

"One time he just came straight out and said 'would you have an affair,'" she told Walters. "...I thought to myself 'don't look him in the eye, stay very busy.'" 

Letourneau told Walters that Fualaau later told her he was in love with her. 

"I said can you hold that for a long, long time," she said. 

Marriage crumbling, Letourneau's relationship with her student turns sexual 

Letourneau told Walters that after her relationship with Fualaau advanced from emotional to physical she wondered: How did it get to this?

"The incident was a late-night, that it didn't stop with a kiss," she said. "And I thought that it would, and it didn't." 

When asked if she felt disgusted with herself, Letourneau told Walters she didn't. 

"For one, I loved him very much, and I kind of thought why can't it ever be just a kiss," she said.  

Even after spending time in jail, Letourneau couldn't stay away 

Letourneau was first convicted of second-degree child rape in 1997 after giving birth to Fualaau's first child. She was paroled after serving six-months in jail and agreed not to have further contact with Fualaau, but shortly after her release, she was caught having sex with the teen again. 

She became pregnant again and was ordered to serve more than seven years in state prison for her parole violation.

In 2004 after her release from prison, Letourneau told Walters that within hours of the "no contact" order being lifted she and Fualaau had reunited. 

Letourneau doesn't believe she stole Fualaau's childhood

In 2015, on the couple's 10 year anniversary, Fualaau and Letourneau sat down with Walters again to talk about their relationship. 

When Walter's asked Letourneau if she stole Fualaau's childhood, she hedged the question and pointed to their time apart while she was in prison. 

"The only benefit if there is any benefit that I was away, is that he had years to be without me and not in a relationship," she said. "I think that even though we did start when he was a young teenager, I was gone for a while, so he had plenty of time to do his thing." 

She told Walters that Fualaau wasn't physically faithful while she was in prison. 

Fualaau struggled with depression and went through a 'dark time' 

Fualaau said having children was a "huge change in his life," and he didn't feel like he had support from his family or friends. 

He dropped out of high school, and his mother was granted custody of the two children he had with Letourneau. 

"It was a huge change in my life for sure, I don't feel like I had the right support or the right help behind me..." he told Walters. "My friends couldn't help me because they had no idea what it was like to be a parent because we were all 14, 15." 

He battled with alcoholism and depression, according to Walters. 

"There's this hopelessness, like nobody understands you, you can't talk to anyone," he said. I wish I'd had a little better guidance through everything ... I don't have a father. My mother is busy too.. no one knew how to deal with it, and I didn't know how to deal with it myself." 

Fualaau warned his daughters about dating 

In the 2015 interview, Walters asked how the couple would feel if their daughters slept with a teacher. Both said they would be shocked. 

“I don't support younger kids being married or having a relationship with someone older,” Fualaau said. “I don't support it.”

Fualaau told Walters he warned his daughters against dating in high school. 

“The reason for me telling them that was just from, out of experience,” he said. “A relationship could lead to something that you think you wanted back then. You don't really want it, maybe, years later.”

More coverage:

Mary Kay Letourneau's husband files for separation