I think it's really cool to have a connection with someone who has completely different interests as you, it's something that keeps you separate and not too close to where your only personality trait is each other. That isn't to say that each party needs to have opposing hobbies, its just nice not to have everything in common. I think too it's what makes relationships not boring, something that leaves a little spark.
For example, my boyfriend is a bit of a nerd (in the most endearing way possible) who likes planes, boats, and star wars, I have been subjected to many 'Did you know?' facts, sister ships, and Skywalker lore. Me on the other hand have a love for cute figurines/collectables, whatever drama is scouring the internet, and reality TV so it's obvious I in turn inform my boyfriend of Sammi and Ron, the newest addition to my collections, and Trisha Paytas' new baby being the pope.
You never know when you have to explain why the F-22 works better than some other fighters, or when you're going to have to understand an TLC reference.
Vent out to your significant other why such a hobby interests you, how a certain something grapples your attention compared to others, that your interest surpasses niche or whatnot. It's okay to not have everything in common, it keeps things alive and leaves a sense of intrigue. Don't get lost in your relationship and lose who you are, you have a soul and heart that sets you apart from the rest.