Hi J.,
The first piece of advice i'm gonna give you is....
1) pick your battles
2) if you don't want him in something bottom line either you tell him "no" or let him get into it.
3) if he wants to through a fit let him and walk off.
I have a 15 y/o and he is throwing a fit right now because he is doing the dishes for the 3rd time time today, whah, whah, whah,lol! Life is a BIG FAT B for him. Why am I telling you this you say and I say because if you try to cater to him now it will only be worse as he gets older. They never do stop the crying, whining, and throwing their arms in the air but then they add words to it such as why don't you just stop talking about me, or the one I heard 5 minutes ago was he knows he is right and thats all that matters right. Like his dad are totally stupid and have no brains in our head. The one thing I'm gonna tell you and everybody else and it starts right now be consistent and back each other up even at this age. Take it from someone who knows the back lashes of not doing it. Agree on what you are going to do if he touches the t.v. or gets into something that he is not to be into. If you both have the same reaction and the same discipline it will help alot. You can agree to disagree but do it behind closed doors where and when your son can't hear you, come to an agreement and understanding and move on. I hope this helps W.