- "I've been dating Derek Wellington for a bit, but I don't think it will last. He's such a boy."
- — Kaitlyn
Derek Wellington is a minor character and past boyfriend to Kaitlyn. He is mentioned when Kaitlyn is talking to Hazel Grace on Hazel's thirty-third half birthday. Kaitlyn is discussing how she wishes Hazel was back at school, and comments that "some of the boys have become downright edible." She then lists a few names, which Hazel doesn't recognize, and states that she's dating Derek.
Kaitlyn doesn't seem to think it will last, based on the fact Derek is "such a boy". Later, Derek himself "dumps" Kaitlyn, and Kaitlyn (while talking with Hazel Grace again) gives some advice; "Remember Derek? He broke up with me last week because he’d decided there was something fundamentally incompatible about us deep down and that we’d only get hurt more if we played it out. He called it preemptive dumping. So maybe you have this premonition that there is something fundamentally incompatible and you’re preempting the preemption.”