My horse Taffy was ear shy, he was very hard to bridle.
I just didn't fight that battle. I completely took the bridle apart when I put it on him,
The English bridle was the hardest, but I unbuckled the left side both the cheek piece and the cavassan, took off the left side of the browband, then put it on him, put the head piece over the top of his head then put it all back together. I did that for the 28 years I had him. I never used a one ear bridle, and never the halter with the clip on the cheek. I eventually got to the point I could clip his bridle path, but never clipped his ears, (never believed in that anyway).
He was so good every where else, I just let him have this vice. Sort of my little gift to him. You can work around it, till your horse gets better about it. My Taffy never did though.