Vicious loop of our desires

Have you ever wondered why our desires never get fulfilled? We keep chasing one after the other. Recently I witnessed the life cycle of one of my longest desires. I was chasing it for years and when it finally got fulfilled, believe it or not I actually observed it vanishing into thin air and taking form of another almost instantaneously. Instead of feeling happy for my fulfilled desire , I found myself looking for other one . This whole episode made me think will I ever be able to get out of this loop or is it something that keeps us going? People say monks have no desires , what made them break that pattern? Guess I will have to figure it out myself. P.S - Here goes my first post :)