Bosshoss I am glad you are moving barns and hope the new one is everything you want.
Now allow me to advise you.
We all teach others how we will allow them to interact with us. You allowed the other BO to dictate how and when you can ride, pet, and interact with your horse. You gave her an inch and she took a mile . She had no respect for you and abused your good nature.
I will assure you that the BO would have moved my horse only once. After standing up for myself, She would never have thought she could tell me not to pet my horse or give him treats. Do you see the pattern here?
Stand up for yourself or you will repeat the pattern again in your life.
I fully understand the anxiety issue and the desire to avoid conflict but you deserve respect not someone who is taking advantage of your good nature. Shalom