Their wedding cake was a Twinkie from a vending machine. The ceremony took place in a prison waiting room. And the wedding night never happened, because the groom was imprisoned as a violent offender and conjugal visits were strictly prohibited.

When Tammi Saccoman, now 63, married convicted murderer Erik Menendez 25 years ago, she knew that it wasn't going to be a normal relationship.

Erik, now 53, and his older brother Lyle, 56, are the notorious Menendez brothers who gunned down their parents at point-blank range with 16 shotgun blasts in 1989. It was one of the most gruesome crimes that Beverly Hills cops had ever seen.

The brothers, then 18 and 21, were found guilty of first-degree murder and conspiracy to commit murder and sentenced to life without parole. Their first trials before separate juries ended in deadlock.

Both young men were inundated with letters from women all over the world. And they soon found love despite the prison walls and razor wire.

Erik married once in 1999, and Lyle has married twice, most recently to Rebecca Sneed, now 51, in 2003.

For decades, every interaction with their wives has been monitored, and physical contact has been limited to brief hand-holding and casual kissing.

Today, both Menendez wives are standing by their men as the hit Netflix series Monsters imagines their husbands as incestuous lovers who murdered their parents after years of abuse.

Where Are the Menendez Brothers Now? Could New Evidence See Them Released From Prison?

What drove these two women to pursue long-term relationships with convicted killers now locked inside the Richard J. Donovan Correctional Facility near San Diego?

Tammi's love story started with a letter of sympathy during Erik's trial in the early 1990s.

At the time, she was living in Minnesota with her husband, Chuck, and her teenage daughter from a previous relationship.

In a horrific turn, Chuck took his own life after being arrested for molesting Tammi's daughter. Devastated, Tammi found herself watching the Menendez trial on TV and reaching out to Erik, hoping to provide comfort. Soon, they began exchanging letters regularly.

By 1997, she had made the trip to Folsom State Prison in Northern California to meet Erik in person.

In an interview with People, Erik recalled her visit: "I remember that when I first met Tammi it was the most beautiful experience of my life. When she crossed the room... Wow! My body lit on fire."

The couple married two years later, when Tammi was 39 and Erik was 29. "It was a wonderful ceremony until I had to leave," Tammi remembered. "That was a very lonely night."

Tammi admits that friends and family thought she was making a huge mistake.

"Everybody questions me. You know, is she crazy? Is she nuts?" Tammi told NBC News. "You know I get all that and so it has been a very emotional experience. The only one that supports me is my mother and his family is supportive. But other than that, it is very difficult..."

Married for 25 years, the two have never consummated their union. California is one of only four states that allows conjugal or so-called family visits, but the Menendez brothers have always been ineligible because of their life sentences and their violent offenses against family members.

"Not having sex in my life is difficult, but it's not a problem for me," Tammi told People. "I have to be physically detached, and I'm emotionally attached to Erik."

Tammi, who wrote a memoir, They Said We'd Never Make It, believes her husband is a changed man and their long marriage proves it.

Erik calls Tammi his "lifesaver."

"Tammi's love was a major step in my choosing life," he told People in 2005. "Having someone who loves you unconditionally, who you can be completely open with, is good for anybody -- to know that this person loves me as I am."

"Tammi's love has propelled me to become a better person," he said. "I want to be the greatest possible husband to her. And this affects the choices I make every day in prison."

"Tammi has taught me how to be a good husband," Erik added. "There is no makeup sex, only a 15-minute phone call, so you really have to try to make things work."

"There is such a longing to share," he continued. "It's not sex, not the physical act you yearn for. It's the communion, just to be able to lay with someone in naked silence. It's hurt not being able to do that. It's not the sex you seek, but the emotional connection."

See Inside LA's Hottest Draw: Menendez Brothers' Beverly Hills Murder Scene

Lyle Menendez, now 56, has had two marriages behind bars.

His first wife, Anna Eriksson, a model and former hair salon receptionist, fell in love with Lyle during the height of the trial in the early '90s. She, too, reached out to Lyle with a letter.

They got married on the day Lyle was sentenced to life in prison, July 2, 1996, exchanging vows over a speakerphone. His brother Erik served as best man and his defense lawyer placed the wedding ring on Anna's finger.

After five years, Anna filed for divorce in 2001, citing infidelity. Lyle had allegedly been exchanging letters with other women behind her back.

Lyle didn't remain single for long. He had known Rebecca Sneed for over a decade before they married in 2003. At the time, Rebecca worked as a magazine editor. Since then, she has become a lawyer.

Lyle and Rebecca have now been married for 21 years, and despite the lack of physical intimacy, they remain committed.

"Our interaction tends to be very free of distractions and we probably have more intimate conversations than most married spouses do, who are distracted by life's events," Lyle told People in 2017. "We try and talk on the phone every day, sometimes several times a day. I have a very steady, involved marriage and that helps sustain me and brings a lot of peace and joy. It's a counter to the unpredictable, very stressful environment here."

Why do women marry violent criminals behind bars? Journalist Sheila Isenberg looked at 35 cases for her book Women Who Love Men Who Kill, interviewing bankers, judges, teachers, and journalists who fell for convicted murderers.

She discovered two categories of women with so-called "hybristophelia," the sexual and emotional attraction to people who commit crimes.

One group falls in love with "ordinary murderers" and believes it sees the "true" good side of the killer, she explained to CNN. Another group is attracted to notorious or infamous killers because "they are drawn to the spotlight."

Isenberg told The New York Times that all of these women typically come from abusive, loveless backgrounds and are attracted by their power to control a relationship with a man locked behind bars. Inmates with longer prison terms are even more attractive, she said.

"The inmate focuses all of his attention on the woman and gives her an enormous amount of love," Isenberg told the Times. "This is a roller coaster love. There are highs and lows, drama, intensity, pain and suffering that can only be provided in the artificial setting of prison."

With the release of Netflix's Monsters series, Tammi and 24 members of the Menendez brothers' extended family released a statement saying the show is "not only riddled with mistruths and outright falsehoods but ignores the most recent exculpatory revelations. Our family has been victimized by this grotesque shockadrama."

"We know them, love them, and want them home with us," Tammi wrote.

"It is sad that Ryan Murphy, Netflix and all others involved in this series, do not have an understanding of the impact of years of physical, emotional, and sexual abuse," she wrote. "Perhaps, after all, Monsters is all about Ryan Murphy."

See Inside LA's Hottest Draw: Menendez Brothers' Beverly Hills Murder Scene

Murphy, the superstar TV producer of the Netflix show, responded to the criticism, saying, "I feel like that's faux outrage."

According to Deadline, Murphy said the series is "the best thing that has happened to the Menéndez brothers in 30 years," adding, "It's everywhere. Their case is suddenly a water cooler conversation."

"A lot of people think that they were dealt a bad hand in that second trial, a lot of people think they should get a new trial, and I think having those conversations are good," Murphy said. "And I know that from prison, the boys have told people in prison that they're glad about this show because it is launching so many conversations. So, if we're doing anything that can further a conversation about abuse and also ask the question is, 'was that second trial fair?' then I did my job."

"There's a lot of controversy about the incest," Murphy told Vanity Fair. "I don't think that the Menendez brothers had incest, personally, but there are people who say they did... This was presented as evidence in court as a theory as to why these crimes might've happened."

Ben Sherwood has tracked the Menendez story since 1989, when he began working at ABC News and helped cover the unfolding saga as an associate producer with an award-winning investigative team from PrimeTime Live.

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