He followed a girl on instagram idk what to do

Me (20) and my boyfriend (26) have been together for 5 months.We are good together but we have talked about his instagram followings.Before we got together he was following a lot of girls and when we talked he removed every single girl that he doesn’t know,that he never met.Since then everything is fine.He is following a lot of girls but all of them are his friends.Today I decided to check who he follows and i saw a girl,no mutual friends and only he is following her,she is not following back.Idk what to do.This i childish to talk about but i feel disrespected like we’ve talked about that and i have said multiple times that i am not okay with him following girls he doesn’t know and is doing this.I am not 100% sure that he doesn’t know her but if they knew each other she will most likely follow him back.Also i want to say that her profile picture is very provocative and her account is locked.Idk what to do should i bring this up?