Hey, Reddit. I wouldn't normally come here for advice, but I'm hoping that someone can give me another perspective on something like this.

To give you a little context: I (17m) got Baldur's Gate 3 as my 17th birthday present last year, and I absolutely fell in love with it. Seeing as I've grown up with a LOTR obsessed father, I've grown very nostalgic of fantasy-themed media, and he was very excited to buy it for me. (This was exciting for me as well, because that game is NOT cheap, but he saved up to get it for me.)
Over the span of months since September, I've been going through fluctuations of being completely enthralled with the game. I have Pinterest boards of my favorite characters, I talk about them frequently, and I sometimes like to draw them when I have downtime.

After playing for a while and understanding how the game works, I decided to show my partner the game. I thought it would be something exciting for us to share, due to the fact that we've been playing a D&D game together with my dad and few other people. I personally think Baldur's Gate is a very good representation of how D&D works visually, and my partner is a visual learner, so I naturally assumed it would click.
They told me once that they get confused watching me play, which was understandable. D&D and all of its intricacies can be difficult to learn for some, so I was patient and willing to explain things to them as I played through the game.
Baldur's Gate, though, for those who don't know, also has a feature where your player character can develop relationships with other characters through dialogue choices. And I was very excited to have my character talk to Karlach, a tall, muscular, and dorkily charismatic tiefling woman. From the moment I saw Karlach on screen, I just knew I'd love her!
Like everything else, I would tell my partner about Karlach and how cool I think she is. I love the progression of her personal story arc, her abilities, and just overall character design. She's so cool hehehe :). Anyways, I thought my partner would be excited with me and encourage me to talk about her more. But they just sort of react with happy emojis whenever I text them about her, and if I ever talk about Karlach on the phone, they don't always have much to say.

I openly tell my partner that I admire this character a lot. I gush about her, and yes, sometimes I giggle like a little boy with a crush. But the fact is that it's never sexual, and it's never more than "She's so pretty! I love her!!" Or, "Omg I get to talk to my wifey :)" while having my character interact with her. And it's not just this one character-- I rave on about other characters that I'm not attracted to, as well.

All of this context leads up to last night: I was streaming the game for them and chilling, progressing further in the story. I was talking to my partner about the characters that I do and don't like, the things I love about the game's mechanics, etc etc...
We eventually got off the phone, and I started sending my favorite pictures/memes/fanart of Karlach + Friends. Their reaction? Just emojis. That's how I knew something was up. They admitted that they were jealous. Like, extremely jealous. And my partner has never been a stranger to jealousy, if I'm being frank.
They told me that they get insecure because she's "everything they're not". I'm still not really sure what that's supposed to mean, seeing as my partner is a human person, and Karlach is a fictional demon woman from Hell. And I'm not ever making my little silly crush out to be more than it is. I'm not telling my partner that I'd get hitched and run away with Karlach if she was real. I just think this game is really cool, and I feel discouraged from talking about it in fear of hurting my partner and making things heated between us again.

Is there any way I can help my partner realize that I truly love them, and not a fictional video game character? Or do I just let them manage it themselves? I don't know if I'm in the wrong or not, so any other perspective would be much appreciated. :)