The trio of Jennifer Garner, Jennifer Lopez and Ben Affleck seem to have worked out an amicable coparenting deal for their blended brood. But sources exclusively tell Life & Style there’s one sticking point that’s causing tension between the Yes Day actress and her ex’s new wife: Ben’s smoking. “Jen and J. Lo have very different views on it,” notes the insider. “J. Lo is grateful Ben is sober, and if he needs to smoke to get through the day, it’s better than falling off the

Jen, 51, on the other hand, thinks it’s a “disgusting” habit — even though she realizes it may be a useful crutch for her rehab vet ex, also 51. “She has strict rules that she expects Ben to follow, like not lighting up around the kids.” The source adds that it “infuriates” the mom to Violet, 18, Seraphina, 14, and 11-year-old Sam that J. Lo, 54, allows the Oscar winner to light up wherever and whenever he pleases.

“Jen’s been very good about not poking her nose into Ben’s affairs,” says the insider. “But this is putting her patience to the test.”