Derek is one of the worst DIKs for me bc he just won't accept you dating Maya, even though she's clearly happy with the arrangement. He's like that even if at the HOTs party you really made an effort to hook him up with girls he liked (Ashley, Penny, Kylie). Same in ep8 with Penny.
Derek knows you like Maya but in ep9 when you tell him you got good news about that, he just asks if you're gonna break it off.
Ironically, he later asks you to speak with Camilla for him, cause he knows you got he's back.
Still, Tommy will prolly react worse. Though I hope he'll be more understanding if you don't have a reputation as a player.