Astute observation. This is a more common tendency than many realise. Heck, most dating apps build parts of the matching strategy on this. I for one find that I am often intrigued by people who have different hobbies to mine, and/or have different jobs to mine. I never dated a software engineer for instance, because for many of us coding starts as a hobby.

That being said, there are people with different hobbies who push theirs onto the partner, naively thinking it helps connect. While it may work for some, I think it's often naive and short-sighted. None of my past relationship involved having common hobbies and that was never a problem. If anything, I found it refreshing and intriguing. It allowed me to have my own space, and she got to have the same. Sure, we'd talk and maybe show each other what we created (one of my exes loved drawing and architecture).

We know that people like echo chambers, so perhaps that's another reason some couples "settle" for each others hobbies as they think "if we both love the same thing, there's nothing to fight about". Some will do it out of pure jealousy, like go to the gym with the wife just to make sure all the other guys know she's taken.

Now you made me list out all my relationships in my head, and no, none of them involved common hobbies. Never thought of that before. But the even bigger trouble was when some of them had zero hobbies. This is why I cannot understand the concept of boredom. When I hear people say they're bored, it frustrates me to no end.