My bf checks his ex's IG stories

My bf and I are open to each other's IG accounts, also for security purposes. But I always see that he always checks his ex's stories, but whenever I check his story his ex never checks

his. I mean duh us girls will never do that right? I just wanna know if it mean anything to guys. For us girls when our exes checks our stories it also gets us thinking right? Am I the only one who's bothered??