I was in the same boat. I flew my trainer, then moved on to a big stik, then this, then that, so on and so on. Eventually I realized that my real passion was buying new planes. I enjoyed the maiden flight then I sold for something else.
It wasn't until recently that my obsession to buy turned to an obsession to fly. It took me somewhere around 15 planes before I found one that kept my excitement.
It was a SPAD. I built the QHOR because it was a "New Plane". Took it to the field for the traditional (Fly land sell buy build). I never looked back. I now sit at my desk all week counting down to those 3 precious hours of flying time I get each week.
Anyhow. I think it comes down to finding the right plane. Flying something that is on the edge of your abilities will help. I am now building a H9 1/3 Sukhoi which is the first plane I bought in months.