Kelly Preston, who died Sunday at the age of 57 after a two-year battle with breast cancer, was a mother of three

John Travolta and his children are mourning the loss of Kelly Preston after a two-year battle with breast cancer.

The actress, who died Sunday at the age of 57, was mom to son Benjamin Hunter Kaleo, 9½, and daughter Ella Bleu, 20, and son Jett, who died in 2009 at the age of 16.

Preston adored her kids — and was "completely blown away" by the addition of "miracle" baby Ben to the household in November 2010, she told PEOPLE in 2011, posing for the cover alongside Travolta and their newborn.

"We had tried for three years, and because of our age we thought maybe it wasn't possible for us. So when we got the news [that I was pregnant], we were completely blown away," she said. "I had no morning sickness. I didn't have a lot of cravings and tried to eat primarily organic, but threw in the occasional mini white powdered doughnut. All my pregnancies were easy, but this perhaps was the easiest."

Of how Ella reacted to learning she'd be getting a baby sibling, "We both told her together right after we found out," Preston said of herself and the Grease actor, 66. "You would have thought Ella was having Benjamin herself because of her enthusiasm about his arrival — she was elated, to say the least. When she first saw him, she fell in love."

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John Travolta and Kelly Preston
Kelly Preston and John Travolta with their kids Benjamin and Ella
| Credit: Kelly Preston/Instagram

Travolta held Preston's hand during the cesarean section birth as Ella excitedly waited outside the hospital room with close family friends, including actress Kirstie Alley. "Johnny laid Benjamin on my chest for me," said Preston, who opted for a silent birth, a practice advocated by the couple's Scientology religion in which few, if any, words are spoken during delivery to give the newborn a calm transition. "Holding him for the first time was magical."

"I was a little nervous because I had never had a c-section before," admitted the star, who gave birth to Ben at age 48. "I have never had any kind of major surgery like that. John gave me an assist, a hands-on Scientology process for getting you into communication with your body and relieving stress."

In September 2011, Preston told Health magazine as she posed for the cover with a then-baby Ben, "I've always wanted to be a mother, ever since I was 11."

"I absolutely adore my kids. Johnny and I love them up constantly," she went on. "Ella's like, 'Mom, ugh! Thank God you had Ben because now he can take some of the kisses.' "

She also said in her Health interview about one big life lesson she has learned, "Don't sweat the small things. Love your kids like it could be the last moment."

Travolta and Preston's son Jett suffered a fatal seizure in January 2009, hitting his head in a bathtub while on vacation with his family in the Bahamas.

In 2003, Preston told Montel Williams that when Jett was 2 he became "very, very ill, but it seemed like flu symptoms" before being diagnosed with Kawasaki disease. The condition, which usually affects children from ages 2 to 5, can cause inflammation of the arteries. Usually treatable, it can lead to lasting heart damage in rare cases.

"What people don't know is that [Kelly's] children are her entire world," a family friend told PEOPLE shortly after Jett's death. "She really went out of her way to make things okay for [Jett]."

The couple have been open about their love for their son and dedication to keeping his memory alive after his death. On what would have been his 28th birthday this past April 13, Preston shared a photo of herself and Jett, writing, "Happy Birthday to our sweetest Jetty, we love you!!"

Preston went on to praise Ella in May 2019, raving about her then-teenage daughter as she made the media rounds to promote her film The Poison Rose, which also starred dad Travolta and Morgan Freeman.

"Still in absolute awe of my stunning daughter @ella.travolta I just re-watched all of her interviews this past week doing press for #thepoisonrose and she has jumped into 'the family business' as an absolute natural," Preston wrote. "It floored me how poised, confident, elegant, sweet, gorgeous (I don't think there are actually enough adjectives in the English language for me to properly articulate how perfectly she held her own)."

The Jerry Maguire star accompanied her note with a photo of Ella and Travolta during an appearance on Jimmy Kimmel Live!, concluding, "I am beyond proud of her and all of her accomplishments, but most of all I am proud and honored to have her as my daughter. I love you and congratulations."

Ella clearly appreciated her mother's praise, as she responded in the comments section, "Awww … thank you so much mama! I love you."

A family representative told PEOPLE exclusively of Preston's death, "On the morning of July 12, 2020, Kelly Preston, adored wife and mother, passed away following a two-year battle with breast cancer."

"Choosing to keep her fight private, she had been undergoing medical treatment for some time, supported by her closest family and friends," the family rep added on Monday. "She was a bright, beautiful and loving soul who cared deeply about others and who brought life to everything she touched. Her family asks for your understanding of their need for privacy at this time."

Travolta mourned his wife's death on Instagram, writing, "It is with a very heavy heart that I inform you that my beautiful wife Kelly has lost her two-year battle with breast cancer. She fought a courageous fight with the love and support of so many. ... Kelly's love and life will always be remembered. I will be taking some time to be there for my children who have lost their mother, so forgive me in advance if you don't hear from us for a while."

"I have never met anyone as courageous, strong, beautiful and loving as you. Anyone who is lucky enough to have known you or to have ever been in your presence will agree that you have a glow and a light that never ceases to shine and that makes anyone around you feel instantly happy," wrote Ella. "Thank you for being there for me no matter what. Thank you for your love. Thank you for your help and thank you for making this world a better place. You have made life so beautiful and I know you will continue to do so always. I love you so much mama."