Her Boyfriend is a ‘Fictionkin’ Who Believes He’s an Anime Character & She Doesn’t Know What to Do

This is a VERY long story that unfolded over 2 different posts, so I have edited it down a bit,

Hi lovely people. Throwaway account for obvious reasons. You know the drill. I tried posting this on r/relationships but apparently the mods there said it was inappropriate. So I am trying my luck here for guidance.

I’ve been with this guy for 3 years and I moved into his apartment some time last year. I love him to bits but lately I’ve been thinking about packing my things and leaving.

My boyfriend has always been a boisterous type and he’s a turbo nerd. He loves his superheroes, anime, gaming, you name it. Whenever we watch anything, especially anime, he’ll talk through the whole thing often criticizing the relationships the writers made for the characters, talk about his “one true pairings,” and he’ll express how certain set pieces in the story make him feel. I’m not into it really but I’ll take time to watch it with him because he makes it rather entertaining and I support his hobbies and interests. He’ll wear his emotions on his sleeve too. He has no problem laughing, cheering, and crying over what’s going on and I love him for that. I love all of him for that. But lately that’s all changed and he’s no longer the person I once loved anymore.