I am gonna avoid an essay answer myself. This discussion can becoming highly philosophical. First of all, it’s a big compliment to you, that he wants to copy your style. It also puts you in the boss slot. He can never get ahead of you, only be a follower.
Anybody can go to a gig of yours (or two or three) and find out your entire playlist. He just had it slightly easier.
As you said, the bugger is in the time you spent searching for it, not the availability of the music itself.
At the end of the day you have to learn to trust your heart, don’t decide based on fear, anger, resentment or any other kind of negative emotion/energy. Take a step back (perhaps meditate a little) and ask yourself what it really means to you from the heart. Then listen to that voice.
Just me, of course.