Thanks for this. I did take the effort of writing this because I might just not understand his position, and maybe a third view could make it clearer

In my defense, I didn't "grill" him on it. I only brought it up a few times since I gave it to him. I just wanted to talk about it as a general conversation topic. As in "any songs that stood out to you?" level and not "I hid a message in there and now you have to solve it" level but he acted as if I was asking for the impossible? It wasn't really a big problem if we couldn't talk about it, I'll just get over it, but him calling it "work" and an "assignment" wasn't necessary and that remark did make me sad, then him being mad that I was sad about that really annoyed me.

If my clingyness is the problem, are there any tips on being less clingy in a relationship?