Boyfriend’s ex love interest

Alright so, my boyfriend doesn’t know that I know he used to like this one girl and tried to pursue her romantically. His roommate is still friends with her and my boyfriend says they’re still friends but they haven’t talked in a while.

Well, my boyfriend’s roommate has a dog and the roommate and the ex love interest are meant to wash the dog together. Either at my boyfriend’s apartment or at her grandma’s house.

I told my boyfriend to tell me when they do,

mostly because I’ve been caring for the dog because the roommate is irresponsible. But it’s also because I want to know if she goes to the apartment and if she’s there, I want to be there.

Am I overreacting? Should I just leave it alone and not have him tell me when they bathe the dog? Our relationship is still new and I am admittedly a bit insecure. Help!