Travolta took to Instagram on Sunday to share a pair of snapshots of Preston, alongside an emotional memorial celebrating her legacy.
"Dearest Kelly, you brought into my life three of the most wonderful children I have ever known," Travolta wrote. "We love and miss you. Happy Mother’s Day."
The post included two family photos, the first featuring Travolta and Preston laying in a bed with their daughter Ella and son Benjamin. The second photo showed the proud parents smiling with their son Jett, who died in 2009 at the age of 16.
The couple's daughter Ella, now 21, also shared a flashback photo of herself and her mom from when she was a young girl, and penned a heartfelt message of love.
"Mama, thank you for all you have done for us and for this world. I miss you and love you very much, but your smile, warmth and love is ever lasting," she wrote. "Wishing all of the moms a happy Mother’s Day❤️."
"I learned that mourning someone, dealing with grief is something very personal," Travolta told the publication. "Mourning is individual and experiencing your own journey is what can lead you to heal. Your grief is different from another person's journey."
"The most important thing you can do to help another person when they are in mourning is allow them to live through it and not complicate it with yours," he shared. "Even though it's great to have company, sometimes it turns into you helping them instead of you working on your loss and grief."