Ben Affleck had a very low-key but “perfect” birthday with Jennifer Lopez. The actor celebrated his 49th birthday on August 15 with his girlfriend, 52, and her twins Max and Emme, both 13, over the weekend after spending time with his own children Violet, 15, Seraphina, 12, and Samuel, 9 — and a source has revealed to PEOPLE that it was precisely “what he wanted.”