For a quick fix, though not the best one, I have seen people use this:
Truthfully, you are over-using your spurs and I have done the same thing MULTIPLE times- for me, it was an issue of riding position- I turned my toes out too much, which was causing me to inadvertently rub the horses side with my spurs. Once I started riding with my toes pointing straight ahead and only turning them out to use the spurs, the rubs disappeared.
I would also recommend a roller ball spur, like this:
They kind of glide over your horses side, so there is less friction to produce a rub. The other thing is making your horse more sensitive to the spurs. be FIRM when you want to use them, and relax as much as possible with them away from the horses sides when you don’t.