Would you be upset if your boyfriend did this??

I’m not usually one to stalk my so’s social media. I never look through their phones because I always allow them to have my trust unless they give me a reason to break it. Recently I’ve noticed he has pictures of his ex in his camera roll and he still follows her on insta. It wouldn’t be that big of a deal but apparently he was obsessed with her and their break up was really bad. He was heartbroken forever. He never wants to talk about her and says he doesn’t want to be reminded of it but he still follows her and has pictures?? He doesn’t even save any pictures I send him (cute mirror selfies, etc) which is what he had saved of her. Apparently he left his last ex to get back with her at one point. Could he really still be caught up with her even after everything??