37-year-old Kristin Cavallari introduces 24-year-old boyfriend Mark Estes to her children, including 9-year-old Jaxon.

37-year-old Kristin Cavallari shared a photo on Instagram Stories of her new boyfriend, 24-year-old Mark Estes, bonding with her son Jaxon, 9. The TV personality introduced Estes to her three children before sharing the photo, which showed Estes and Jaxon having a conversation with their backs turned to the camera. Cavallari shares children Jaxon, Camden, 11, and Saylor, 8, with ex-husband Jay Cutler.