What's our (couple) thing???

My boyfriend likes Anime. I used to like it in middle school, but became uninterested when I started high school. We're both nerds, but he's more nerdier than me. We've been dating for almost 4 months now, & he wants me to get into Anime, so that could be our thing. like, even going to the nerd conventions & dressing up. I don't have a problem trying to get back into Anime, but for these past few weeks, I can sense that he's getting frustrated with me forgetting things that are a big deal in Anime related things that he shows me. The first time we had this conversation, it led to a bad-ish argument.

Tonight, I'm not even sad or mad about it, but disappointed? I mean, he. was a bit pissed about me forgetting things again. especially since I kinda fell asleep too. How do we find our thing as a couple because although I don't have a problem trying to get back into anime, I'm pretty sure there's many other couple things that can be our thing. I just think he wants anime to be our only thing, when our thing can possibly be many things. We just haven't found our own thing yet. I don't know what to do, but I really would like some kind of advice because if we have to have one more conversation like tonight's, I'm probably gonna get annoyed.

I was afraid of even having to have a conversation like this again after the first time this happened. Someone please give me some advice. I'm begging you. Thanks in advance.