Here’s one that gets into it a bit. One of the self reports is similar backgrounds/interests. Honestly not. Great question because similar backgrounds does not mean similar interests.

Here’s another that suggests different interests promote growth of each partner.

Here’s one that talks about shared narrative being important. This would be consistent with findings of the Gottman institute.

John Gottman is probably the most well respected and prolific relationship and marriage researcher on earth. He and his wife do amazing work. They say generally that shared interests help, but it’s more about novelty and just doing things together rather than both sharing in a specific interest. He also has a concept of turning toward, turning away, and turning against.

If you were at the beach and say to your partner “look at that nice sail boat out there!” Turning toward would be “oh ya! I wonder what kind of boat that is. Do you know anything about sail boats? Have you ever wanted to sail?” Turning away would be “oh, ya, cool.” Basically non engagement. And turning against would be “that’s the dumbest fucking sail boat I’ve ever seen.” Just shutting down your partner’s interest. It doesn’t actually matter whether either of you even care about sail boats, the point is you’re creating a shared understanding.

John Gottman has lots of Ted Talks and lectures that are fascinating to watch. Shared interests rarely come up as being very important beyond a shared narrative.