Jennifer Lopezis married to Ben Affleck -- and wants all the other ladies who still might have eyes for him to know it ... evidenced in how she barked at some onlookers Sunday.
The couple was out on the town in L.A. this weekend, and before Monday rolled around -- they were leaving dinner at The Ivy together ... with BA playing the gentleman for his wife and opening the car door for her, while going around the other side once she was in.
Ya gotta see the video, because J Lo's feisty clap-back is classic Jenny from the Block -- although, it's unclear if the women on the other end heard her. One person who certainly did hear her jab was Ben himself ... so he definitely knows he's hers and hers alone.
Single ladies, be warned ... if you come at Ben around J Lo, expect her to clap back!!!