Perhaps Rumple didn’t create the curse. We know he doesn’t have the darkest heart in the land, since Regina didn’t require his hair to enact the dark curse like she did from others in ep. 2. We also know Regina didn’t create it either, nor Maleficent, who said, “Whoever created that monstrosity makes us look positively moral.”
In a recent interview, Robert Carlyle hinted that there could be a twist to the show's curse in that the curse may have surprising origins. He also said that relations between Rumple and Regina are going to become far more strained. “Certain things happen toward the last five or six episodes that shake our relationship,” he teased. “You realise that maybe Rumpelstiltskin [didn't create the curse] for her at all – maybe he was doing it for himself. Maybe the curse was created for him.”
http://www.digitalspy.co.uk/ustv/s181/once-upon-a-time/news/a369793/once-upon-a-time-robert-carlyle-hints-at-curse-twist.html
Also, I can't help but wonder if Cora, Regina's horrible mother, might be the one who makes Regina and Maleficent “look positively moral.” (i.e. Cora created the curse).
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy