I can totally relate to you! My horse has never been particularly dangerous, but I feel like we've never clicked. I tried Natural Horsemanship that is similar to Parelli, which helped my horse some, but did nothing for me. I like the mindset of NH, but now that I've been exposed to "classic" riders (lol! I changed barns which has helped me through more than just my horse!) I feel like NH is just not for me.
Since I've just found out my horse is 23, sold to me as "13", he's been having a lot of health problems since I've been riding him more. I feel like it is unfair for us to stay together. I wish we could, but we just aren't right for each other anymore. He needs a lighter work load, pleasure. I want to ride everyday and do different events.
As hard as it has been to make my decision to sell him, I've had the confidence. We're putting a little more weight on him, then he's going on a few different sale websites. I feel absolutely horrible, but its what we both need!
Don't feel bad about selling your horse! Do it because that's what you both need and one day riding won't be so chore-like! I've started riding my friend's horse and I'm already having more fun! Remember, riding is not something you should just have to do. Its for fun!
Good luck and have fun