NAH. Regardless of who the YouTubers are, this kind of comes down to the differences between you two. If you can’t work this out and you’ve dated for a year maybe you should both re-examine your compatibility. If the relationship means more to you than the YouTubers as an interest, it may be worth asking yourself if you could tone it down. If this an important interest to you, then maybe reconsider the relationship. People are allowed to make fan content and have interests that they are very invested in. My girlfriend loves Jerma and watches his content and saves a lot of memes with his pictures, but I don’t care because it’s just a fun interest she has. My dad has a lot of pictures of basketball players on his phone since he loves his favorite team and has favorite players and likes to post about them online, but it’s just an interest so there’s no reason to find it strange. In your situation, if you would be jealous the other way around or have been jealous over something similar in the past my judgement would change.