Ben Affleck and Jennifer Garner share three children, daughters Violet, 15 and Seraphina, 12, as well as 9-year-old son Sam
Ben Affleck,Jennifer Garner
Ben Affleck, Jennifer Garner
| Credit: Magnus Sundholm/Shutterstock; Jon Kopaloff/Getty Images

Ben Affleck is honoring Jennifer Garner on Mother's Day.

On Sunday, the actor, 48, shared a sweet tribute to his ex-wife, with whom he shares three kids: daughters Violet, 15, Seraphina, 12, and son Sam, 9.

"So happy to share these kids with you. Luckiest parents in the world. Thanks for all the good you do. Happy Mother's Day. Love, their Dad," Affleck wrote, along with throwback photos of Garner with their children, including a family photo from a past Halloween holiday for which he dressed as the Tin Man.

Speaking to PEOPLE last year, Affleck said that he and Garner, 49, have always made a point of being united for their kids.  

"When you have children with somebody you're connected to them forever," the father of three said. "And I'm very lucky she is the mother of my children."

"I'm very grateful and respectful of her," he added of Garner. "Our marriage didn't work, and that's difficult. Both of us really believe that it's important for kids to see their parents respect one another and get along, whether they're together or not."

Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday.

Affleck shared that it's vital to him that his children know how much admiration he has for Garner.

"It's important for my kids to know that I respect and care about Jen and she treats me the same way," he said. "I have a lot of respect and gratitude toward her. And I wish her the very best."

Affleck and Garner, who married in 2005, announced their separation in June 2015. They settled their divorce in October 2018.