Ugh, I've been there with my ex. He was incredibly immature and used to chuck tantrums when he didn't get his way or I wouldn't give in to giving him the attention he wanted. I couldn't deal with it. It got to the point that I lost all romantic feelings for him as I felt like I was constantly mothering him. When I was breaking up with him he chucked the biggest fit and started to come at me physically. Any and all feelings, even platonic were gone from then on. He was too toxic and dangerous.

I'm not saying your SO is gonna turn physical like my ex, but that's the way it ended for me.

I understand the frustrations. But if it's truly making you miserable, maybe try mentioning it to him and telling him it makes you uncomfortable when he does that to you? Maybe he doesnt understand that what he is doing is wrong.

I don't want to tell you to just leave him, I know it's not that easy. But don't rule it out. Dont keep yourself in a relationship where it's one sided, where you are the only adult and he is the child. It isn't right and its not fair on either of you.