Ben Affleck Celebrated 44th Birthday With Family Trip to Montana

(Photo: Angela Weiss/FilmMagic)

Happy belated 44th birthday, Ben Affleck!

The Batman v Superman actor celebrated his Aug. 15 birthday with ex Jennifer Garner and their three children while on a family trip to a Montana resort where they own a condo.

“The family spent the week together and enjoyed outdoor activities like hiking, biking and swimming,” a source close to the couple tells PEOPLE.

Despite separating after 10 years of marriage in June 2015, the actors have maintained an amicable relationship, the focal point of which is their three children Violet, 10, Seraphina, 7, and 4-year-old Samuel.

The family has spent a large amount of time together, including a month-long trip to Europe during the summer while Affleck was filming Justice League in London.

“Ben is happiest when he’s spending time with his family,” adds the source. “It was a great birthday.”