They were arraigned and appeared jointly in court in April and released on $5000 under the condition of staying away from each other.
Mares was also not allowed to see any of her other nine children. It is unclear who was taking care of them.
The couple could have received up to 18 months in prison but District Attorney Andrea Reeb, who prosecuted the unusual case, said that the pair had no criminal record and treatment was more important.
Previously, however, the couple had said nothing would stop them from having a sexual relationship.
In August, the controversial couple, who connected on Facebook 18 years after a 16-year-old Mares gave up her son, who was then called Carlos, went public with their story in an effort to raise awareness of Genetic Sexual Attraction (GSA) relationships.
In exclusive interviews with Daily Mail Online, held separately so they wouldn't breach their no-contact order, they told how they are willing to risk everything to be together.
GSA is defined as sexual attraction between close relatives, such as siblings or half-siblings, a parent and offspring, or first and second cousins, who first meet as adults.
In the interviews and before the pair didn't know they would be spared incarceration, Mares said of her eldest son: "He is the love of my life and I don't want to lose him. My kids love him, my whole family does. Nothing can come between us: not courts, or jail, nothing.
"I have to be with him. When I get out of prison I will move out of Clovis to a state that allows us to be together."
Incest is a crime in all 50 states, but the specifics of the laws and punishment vary greatly from state to state.
Mares said she would even give up the right to see her other children if she was asked to choose between them and her lover.
The couple embarked on their love affair towards the end of 2015.
Mares saw her son for the first time in 18 years last Christmas when she picked him up at his adoptive father's house in Texas and brought him to her home after the pair got in touch over Facebook.
The couple soon developed romantic feelings for each other and their relationship became sexual a few weeks later.
"The first time I met my son in person I was so happy and excited I gave him a big hug," Mares said. "I went to go pick him up at his dad's house in Texas.
"He gave me a call and asked me to pick him up. I got butterflies in my stomach.
"I met him outside and I knew it was him when he came towards me. He was crying and he gave me a hug.
"It was almost love at first sight but first it was mother love. He gave me a mother hug.
"He came home in the truck and came to live with me and we were both happy as mother and son."
Mares said that at first nothing happened but she then started getting "crazy" feelings.
She said it felt different because she didn't raise him as her child, but after all those years he came back to her.
"It felt like I met somebody new in my life and I fell in love with him," she explained.
"At first I told him, "I'm sorry I don't know how you are going to react to this. I'm your mom and you're my son, but I'm falling in love with you".
"And he said: 'You know what? I am too. I was scared to let you know.' He was falling in love with his mum and I was falling in love with my son.
"We talked about it and we took off to the park. I said, 'Would you ever date your mom?' And he said: "would you ever date your son?' And I said, 'Honest truth yes I would'."
Mares said Peterson was the best thing that has happened to her in the past 19 years and wanted to be with him for the rest of her life.
At the time, she said she understood that she risks losing all her children and going to state prison but they both want to fight for their right to love.
"Caleb is willing to go through the same thing. Whatever it takes to be together," she said.
At first the couple lived happily together in Mares' mobile home with her youngest children Uriah and Joseph - keeping their relationship a secret from the world.
Mares' youngest son even began calling Peterson "Dad".
But their unusual arrangement imploded when police were alerted.
Mares said the potential of imprisonment and having her children taken away was all worth it to love the man she loves even if he's her son.
"It is every bit worth it," she said. "If they lock me up for love then they lock me up. There is no way anybody could pull us apart, and I really do love him.
"It hurts he is far away. It hurts really bad. I wish I could see him, talk to him, but I can't risk it."
Peterson said he started falling love with his mother about a week after meeting her - but claims as he grew up with adopted parents he never saw Mares as his mother.
"I never had anyone cook me meals or give me anything," he said. "I never got anything my entire life and she went out of her way to make me happy and after about a week or so I started having feelings for her and I guess I fell in love.
"It went beyond a mother-son relationship I never really viewed her as my mom. In certain aspects I do but mostly I don't.
"I never thought I was crazy for having these feelings because I didn't see her as my mom, it was more like going to a club and meeting a random person. It didn't feel wrong, it felt normal."
Peterson claimed he made the first move, not his mother.
He recalls: "We were hanging out just talking and I looked at her and she looked at me and I kissed her.
"It was a real kiss it had feelings behind it, there was a spark that ever since then it just stayed.
"Honestly I never thought we would get into trouble for our relationship. We were both consenting adults - when it comes down to it.
"She's adult, I'm adult. I can make my own decisions. I never thought it would blow up into something like this."
As well as legal trouble, the couple met opposition from friends, neighbours, family members and the wider community.
Mares has been attacked outside her home and subjected to death threats.
She said: "I've been having a lot of trouble from the people in Clovis. They call me incest."
Mares says other mothers she knows don't understand what she's going through but says her kids have said they will love her no matter what.
But with a torn look on her face, she added: "But if I had to choose between my son and all my other kids I'd chose him."
Peterson added: "My dad walked out on me because of it.
"There's a lot of negative comments I read on Facebook and things - people say it's disgusting, it's gross, she's your mom but it doesn't hurt me or affect me at all.
"If they were in my situation or if they were to find out that somebody they loved was actually related to them then they'd be saying the exact opposite."
Peterson admits that sometimes he wonders if he should have done things differently - if only to spare his family the pain.
In the interview, Peterson said even if the judge offered to spare him jail if he stopped all contact with his mother, he would refuse. He also vowed to wait for his mother if she was given jail time.
"Sometimes the easy way isn't the best way," he said. "Sometimes we have to make that life decision that's going to change and affect everything but when it comes down to it, it's worth it.
"I will wait for her if she gets a jail sentence and I don't. For me it's not about patience it's about commitment.
"If I'm committed to something I follow it through that's the kind of person I am.
"If I love her enough and I'm crazy enough to stay in Clovis for her and crazy enough to face all the courts for her then waiting a bit of time to have the rest of my life being happy then I'm willing to do that."