They grew up together, more enemy than family and avoided each other as adults until they couldn‘t.
Christopher is a jerk, Kate seems to be missing all the skills and fortitude that allowed her to be a globe-trotting photojournalist, the author seems to have forgotten Kate‘s family is close and loving.
I‘m not a fan of age-gap romances and while 6 years isn‘t bad, Christopher‘s habit of constantly comparing adult Kate to child Kate got creepy.