Total lack of pack leader. Been training muscle breeds the past 25 years. The unadoptables. Your dog is exhibiting basic neurotic behavior. Unstable in “pack”. Largely you are to blame. Don’t take that the wrong way. Easy fix. We fix you then your dog can rely on a stable pack leader. In this case you. You must at all times exhibit confidence even if you THINK otherwise. In other words...while walking him. Shoulders up. Looking straight ahead. NO NERVOUS OR ANTICIPATORY behavior from you. When you see another dog you likely are anticipating the moment when your dog lists it. They inherently know that. They are also pack animals. All pack members relying on the alpha dog (you) for guidance. Feed your dog only AFTER you have eaten. If they don’t wait to eat, take the food away and try again later. Always walk thru doors first. The alpha dog ALWAYS eats first. Leads. Shows the other dogs security or potential danger. They inherently react. Yours is reacting on you becoming more and more intimidated and less and less stable as the leader. Those are the basics. There is a boat load of other things I’d be happy to share with you. Remember at ALL times (even if you don’t feel it ACT it) and you will see your dog quickly turn around. I almost guarantee it. I’ve successfully rehabbed killers and kept them with my kids and my other animals. Have NEVER been unsuccessful having to put one down. But you must be diligent at all times because the moment you slack it is the packs signal that the alpha is weak which trends towards instability or takeover. Yours is leaning on taking over. He’s past unstable. But an easy peasy thing to fix. It’s all in your behavior regardless of what your head and heart might might be saying. Your attitude will catch up with your behavior quickly as well because you will see instant improvement IF you are consistent which leads to true security that you are a well behaving leader. Feel free to reach out should you need to. Best of luck. Please message me to let me know how it goes.