TWO THINGS CAN BE TRUE AT ONCE: Jack vs. Ciara situation Ep 1-5
Jack clearly has ADHD (self-proclaimed) and only hears the headlines. And so, when Ciara said that he was in her top people, he unitentionally heard that they were each others top ones. I think that was a genuine mistake. However, Ciara is right when she said that he likes to stretch the truth. He could tell that she was going to break it up, and he indeed broke it off because he couldn't get rejected first. The whole back and forth was awkward and you could tell he felt some sort of pleasure telling her that date was boring.
In all, neither deserve the people they're with.