AIO - bf is keeping inappropriate pictures and videos of past partners.

My (34f) bf (36m) is keeping inappropriate videos and pictures he took with other partners during a time when we were apart. This bothers me. I told him it does and he won’t delete them. He said he wants me to ask him to delete them. I feel like I expressed my feelings clearly and if it mattered then he would delete them or explain why he wants to keep them. I don’t know if I’m being immature or if this is some kind of mind game. I’m also open to listening and trying to understand how I may be wrong for feeling like I do about the material.