No horse rears for no reason. Maybe YOU can't see the reason...but they HAVE a reason. It's the same thing with any other animals.
They do have reasons, it just might not be apparent to you.
I used to ride a Gypsy Vanner and one time I asked him to stop and he reared up. I didn't know what he reared up on, but he HAD a reason. They don't do it "just to do it" and even if they did, that would be their reason.
He's testing you, and you let him get away with it twice.
If you are so experienced, why are you getting so uptight about us commenting. You asked for our help, input, and suggestions. And we gave you them.
Also, I was reading one of your other posts, if you are experienced, how come you can't get a horse to turn? I'm sorry if that sounded rude, it wasn't meant to be. But seriously. It doesn't sound, to me, that you are ready to take on a stallion.
My suggestions are either geld him or sell him.
That's my suggestion and my opinion, if you didn't want to hear my opinions and such, then don't ask for peoples opinions and help