In any healthy relationship there are joint interests as a couple, and individual interests for each person. Things that are important to them should be important to both, as getting support from the person you love most is really important. And letting them know that you care about them and their interests regularly counts.
What to do: You don't have to join them in all their activities/passions, but paying attention to what matters to them—and being genuinely interested in it—will make all the difference. Carve out some time to talk about what they are up to, without the need to share your stuff at that time. By allowing them to have center stage, they will feel the value you are giving them. Then — have them reciprocate.