I don't know whether this will get read but I just want to offer up some different perspective. Initially, with my boyfriend, I'd act the same. Get upset over petty things and really make him chase me and appease me. I'm not really proud of it but I guess I had some of my own issues. I knew I'd be doing it but I just wanted to know if he'd be the same with me even if I was difficult - I'd been cheated on before and I just needed to know I was investing feelings into the right person so every time I acted out and he still cared - I'd feel assured that maybe he does have real feelings for me. But after a while, this started to become a habit on my part - I was conscious of it but couldn't really control it and obviously after some time, he started to get fed up, continuously having to walk on eggshells. So slowly over time, he started to snap back at me and tell me he wasn't going to take it from me. I didn't really like losing the control but it did make me realise I was being a really big baby and in a relationship, I couldn't always be right or have it my way. Though I knew this from the start, the fact that he took it and tolerated it, made me do it more, I guess. But I also knew it had to stop and him being firm with me has helped me. Since then, I have told him why I acted like that at times and he understands. And also, throwing tantrums all the times confuses the other person and they won't know when you are actually upset for real. Now, I don't get upset over small things and I'd only ever cause a fuss over something big and my bf will know I'm seriously upset - not just looking for attention or a way to control the relationship.
My point is sometimes its easy to for habits formed at the start of the relationship to spiral out of control even though the other person may not mean to and maybe they have a reason behind their 'childish', 'unjust' behaviour and if you sit there and take it, they won't have a reason to stop it. If you want it to stop, make it a point to stop it and treat them the same way if that's what it takes so they realise how it feels when its them on the other side. And if you mean as much as they mean to you, chances are they'll make the changes needed though obviously habits take time to break - just keep that in mind. But definitely don't just let it slide each time.