Ben Affleck spent the holiday with his three children with estranged wife Jennifer Garner — daughters Violet and Seraphina, and son Samuel

Ben Affleck wears many hats, but he was in full dad-mode leading up to Father’s Day.

A source tells PEOPLE that the actor spent the holiday with his three children with estranged wife Jennifer Garner — daughters Violet, 12, and Seraphina, 9, and son Samuel, 6. He was spotted taking the two younger children to Dunkin’ Donuts in Santa Monica on Sunday.

Affleck, 45, has been in Los Angeles all week doing activities with his kids, including attending Violet’s graduation from Carlthorp on Thursday and celebrating with lunch at Ivy at the Shore after.

The insider added that the children have been spending a lot of time at his home, so his girlfriend, Saturday Night Live producer Lindsay Shookus, is likely not in town.

The Oscar winner also celebrated Father’s Day with an Instagram post featuring a card from one of his children that reads, “Love you, Dad! You are my superhero!”

“I can think of three incredible reasons why today is so special,” he captioned the post. “Happy Father’s Day to all the dads and father figures out there, and to the women that empower them to be the best they can be. We are all so fortunate beyond measure.”

Garner, 46, shared a dedication to her ex, a sepia-filtered photo of Affleck with a sweet shout-out about his parenting. “Our kids are lucky to have a dad who looks at them the way you look at them and loves them the way you love them, @benaffleck. #happyfathersday #threeluckykids #haveagreatday,” she wrote.

The famous duo separated in 2015 and filed for divorce last year, but have maintained an amicable relationship for the sake of their children.

“The kids love when they all spend time together,” a source told PEOPLE. “As long as Ben keeps working on himself, Jen is happy. She will continue to support him because it benefits the kids.”

85th Annual Academy Awards - Arrivals
Jennifer Garner and Ben Affleck in 2013
| Credit: Jason Merritt/Getty

Affleck’s Father’s Day holiday comes after recently wrapping his film Triple Frontier in Hawaii, where he threw the film’s cast and crew a traditional Hawaiian luau.

A source told PEOPLE that Garner made a trip to Oahu with their three kids to visit Affleck for Easter.

Ben Affleck and Lindsay Shookus
| Credit: John Salangsang/Invision for FIJI/AP Images

Shookus also visited him on set, with the two spotted holding hands in Honolulu in March.

A source previously told PEOPLE that Affleck and the producer, 37, are “very much still together.” Another source said the couple is “not rushing anything,” but that they “enjoy each other’s company” and “are in a committed relationship.”

Affleck and Shookus first stepped out publicly as a couple in July.