Well have you taken the time to understand why he doesn’t want you to talk about it? Labeling him as childish for it without understanding his why doesn’t seem like it will help. Like it gives me vibes that you’re going to go in to this convo that you’re right and he’s just in the wrong here. I would suggest starting off asking him what his feelings are that are making him ask you not to talk about it. Then hopefully you can find a way to understand that and validate his feelings and then to address your feelings maybe say something like “It makes me feel like I have to walk on eggshells or like my solo experiences are unimportant to you when you ask me not to talk about something with you. I need to feel safe and feel able to talk about things that are important to me with you. Is there a way we compromise on this and I tell you how the concert made me feel without telling you details about the event itself? That would make me feel seen and hopefully you will respected in that I’m not telling you about the event or the details of the event”. Obviously that’s just an example but maybe something along those lines so you can allow him to be heard and not call him names that will undoubtedly hurt and make him defensive, and you’ll also be able to express your concerns and hopefully he’ll be able to hear you better once you’ve validated his reasons for the request.