HELP - Rick Gore Horsemanship

Question
I promise I watched all the videos that I could and some concerns were answered, thank you, however I have a million more but will throw this one out there and hope you can help me see where I need to adjust my thinking and figure out how to help my boy and me. I have a gelding...sweetest temperment, looooowww man on the totum pole, but he has fire in his eyes and has always been  willingly to put up with my odd request of him, he's a horse I always figure anything that we want them to do must seem very odd to them. Sorry for babbling, we have 4 horses in our pasture 2 geldings, 2 mares, well a few days ago a new mare was introduced to our herd and BAMM!!!! my little sweet gelding is dangerous!!! He's not allowing the new mare anywhere near what all of a sudden looks to be his herd, he snakes his head towards the other mares and moves them where he wants them and chases her away. Well I went to call them all for feeding and he refused to come, he actually could have cared less who or what I was and he just mowed right through. Stupid me went after him got him by his halter and walked off with him  and he followed me until I got to the top of the hill and I could see that he was more than just thinking about rearing up on me, I released the halter let the line through my hand and he started to herd me towards the fence. I stoppped stood still got his eyes on me and asked him to back up, I wanted to see if any of him was with me, he took two steps back, but I was now afrraid of my boy. Rick what happen to him? before this new addition showed up he was content in my company even if the others where down in the pasture, now OMG! he truly scared me and I am not sure how to approach him. While he was eating he was his old self quiet, stood like a gentlemen to be groomed took a nap next to me. What did I do wrong, how do I make sure that doesn't happen again, do I allow him to act like that, will it go away, he shocked the crap out of me, would love your knowledge of the horse here.

Answer
Well that is what you get for sticking your nose in horse business when you don't what you are doing. You went out there thinking you were smarter and was going to save horses that DID NOT ask for your help, that  did not need your help and since you got involved you now taught the horse you do not know what you are doing.

Perhaps had you stayed out of it and let horse be horses and if you had heard anything I say like horses are the best teachers of horses (not humans), then maybe you would not have taught this horse that you are weak, not horse smart and not a good leader.

So congratulations, you are officially a horse trainer, too bad you trained your horse that you are lower and that he should not trust you and put his life and safety in your hands.

Now what?

If you would  have taken your time, read my site, watched all my videos and not just all you could, then you would know what is going on, what you did and how to correct it.

I am not going to make it easy for you, so either invest the time and learn what you did so you can fix it or run around ask others to help you and probably get bad advice that makes it worse and not better.

Your choice, just like it was your choice to get involved and stick you nose in and try and save horses that did not need saving. When you make poor decisions you get poor consequences. You are lucky you got a free lesson from this horse and he did not teach a hard lesson that cost you more that just your pride.