First of all, you are so NOT a terrible rider. Are you kidding? you aren't perfect, but who is?
If you want a critique of your riding, I can give you some pointers. But the thing is you recognize a fundamental part of yourself , being timid, that you think will never change. And you want to have a horse that matches well with this fundamental part of your nature. I think this is very wise of you.
And it sounds like you had to go through a bit of "hell" to get to this decision. I salute your courage.
I know this one aquiaintance how kind of inherited two horse that were WAYYYYY too much horse for her. She was very fearful of horses, but determined to learn to ride these hroses. She was fortunate to find herself a really good trainer , who works using natural horsemanship basic philosophy and techniques (ala Buch Branaman and Bill Dorrance). My friend worked and worked and worked with this trainer. HOURS and HOURS of work. I dont lknow how she afforded it. I could not have done that. I would have sold those horses in a heartbeat. IN any case, anyone who knew her would not imagine her capable of riding them out on the trails, yet 2 years later, she is doing this.
It is because she found the right person who NEVER EVER belittled her for her fear and kept being ever confident that she could do it. and she did!
If you can find the right person to help you, and a good horse that is as reliable as a horse can be, (and they DO exist) you will have that place in your heart that longs to be happy with horses fulfilled.
AND, again, you are NOT a bad rider!!!!