I've had horrible luck, too! My last horse gave me a dent in my leg that has no feeling in or around it.. It is now about 9 months old and hasn't changed a bit.
I'm pretty sure I finally found my heart horse and am hoping for MANY years to come with him!
You are definitely lucky! I never had a trainer (until English lessons last year). If my horses were out, then they were out and I had no others to race. Plenty others to ride, but only two of them were finished barrel horses.