ok so i been noticing all day that when i get off the stolen horses (cuz i cant afford yet on thie character to constantly pay out 1,000 gold for new horses all the time so i been stealing them) that the horse disappears. up till now i thought the horse got lost fallin off a cliff or something till it happened again just now and i happened to turn the cam as i got off the horse at the right angle to see the horse sbichdically fly backwards towards the stable i just stole it from...

Stolen horses return to where you stole them from.

http://uesp.net/wiki/Skyrim:Horses

This.