, it probably is a disrespect problem.
I haven't changed the saddle, nor the girth. And even though he's sensitive to the foot and has a soft mouth, his trainer handles that very well: he rides him sensitively and is verrrryyy patient with him.
I experiment yesterday with something:
He wouldn't let someone ride him in front of the stables (the riding line), so the trainer mounts him inside the box, which could be very dangerous, but once he's out for his work, the trainer dismounts and mounts again, and the horse has no problem with being mounted in an empty place with no other horses or distractions.
I understand that stallions are easily distracted, but I don't think this should be an issue when it comes to riding him. What should I do to get over this hurdle?