Affleck and Lopez have been spotted together several times since her split from Alex Rodriguez.
A source tells ET, "Jen isn't bothered by Ben hanging out with J.Lo or anyone else. She wants what is best for Ben."
The 49-year-old mother of three who shares her kids with the Justice League star has other priorities when it comes to her ex.
"What matters most to her is Ben being a great dad," the source continues. "They've been in a good groove when it comes to co-parenting for a while and their kids' happiness is Jen's main priority."
Garner and Affleck were married from 2005 until they separated in 2015. Their divorce was finalized in 2018. They share daughters Violet, 15, Seraphina, 12, and Samuel, 9. Lopez and Affleck were engaged from 2002 to 2004.
"Jen and Ben have remained friends over the years and the two are still just that - friends," the source told ET earlier this week.
Another source confirmed the friendly nature of their current relationship.
"They obviously have a romantic history, but at this point they only have a friendship," the source said. "They both admire each other professionally, respect one another and feel comfortable with each other."