Well, if you're happy with the way your horse is going and don't need any immediate fixes, I might put off the issue a bit by saying, "I can't really afford any extra training rides this month," then take a while to evaluate whether the lessons you're getting are going to be enough progress for you and your horse without frequent training rides.

However, if your horse is at a stage where you really do need that pro ride, but you don't want to leave and burn your bridges with this trainer, you're going to have to sit down with him and discuss in what areas you think he and the horse are not clicking. He may feel the same thing and not be willing to admit it, or he may just have different goals for the horse than you do and he can adjust his rides to align with your goals. If he's really not able to click with the horse, is there a working student or competent schooling rider in the barn that can try the horse, so you can remain there?