THE RUNDOWNA source shared rare insight about Jennifer Garner and John Miller’s relationship. The insider also explained why Miller is “completely comfortable” with Garner and her ex-husband Ben Affleck spending time together. Jennifer Garner and CaliGroup CEO John Miller have kept their relationship mostly private since they first became romantically involved in 2018. Miller has no issues with Garner’s relationship with her ex-husband, Ben Affleck, either. BACKGRID Jennifer Garner and John Miller together in April 2025.