That sounds really tough :(
Before it all started do you feel you had a good relationship with him? Do you spend fun time together with him now? Has there been any major changes in his life recently? Is he moving schools in September maybe? It's such a tough age and I'm sure there's lots of people in your position.
For questioning decision making, maybe there are some times you could involve him in making the decision? Maybe he has some good ideas? If he tries to offer suggestions on things it's not his place, you can tell him so " I appreciate your views on other things but this needs to be my decision."
In what way does he embarrass you? (don't forget that real friends will be helpful and supportive of you!)
What actual consequences do his actions have, other than him getting to enjoy your uncontrollable anger, seeing how much power he ca have over you?! (No judgement here!)
You need to sit down with your DP and talk about natural consequences to his actions. And get some ideas on how you can manage when you feel the anger growing. Then sit down together with your son and talk about the actions and why he thinks he does them. Talk about the consequences you and dp have agreed on, and maybe write them down. Also say that you have been finding it hard to manage your anger but you want to do better, and your plan for what you will do when it happens. (Bathroom locked and iPod on?)
Plan some fun stuff together but do not threaten to not go if he misbehaves. To me it sounds like he needs the time with you with no agenda other than quality time.
My dd is 12 and can be v hard work and even violent. I know the best thing for me to do is stay calm, ignore or sweep toddler and myself off somewhere safe.
Once she's calmed down we talk about how she felt etc.
it's def not always easy to do. And she rarely does it in public, which I can imagine magnifies the feeling a lot!
She has recently been diagnosed with ADD and the symptoms have caused he a lot of stress at school and home. It was causing her to feel depressed and out of control. She tried to get it back by playing up with me.
If she's whining " can't you hurry up and finish this shop already im bored" then she gets a shopping list to speed things up. I Try to sympathise " I wish we didn't have to walk this far either! If I could, o would Magic up a couple of segways/flying unicorns...
We do ice cream "dates", I watch her play minecraft (kill me now!) or play board games.
It's draining but we are mostly argument free.