Well...I've just read the biography "The Last Train To Memphis" and "Careless Love"...Elvis loved women and he had many girlfriends before Priscilla. The most "famous" were Dixie Locke, June Juanico and then Anita Wood. But at the same time he dated many others girls...Barbara Hearn, Natalie Wood, others met in Las Vegas (Marilyn Evans and Dottie Harmony), Yvonne Lime and in Germany Elisabeth Stefaniak...and others before meeting Priscilla months after.
Anyway, it's hard to say how much serious were all his relationships...at the beginning Elvis thought to marry, then he started also to have fun as every other guy (he could meet easily a lot of beautiful girls). I still consider the most important girlfriends Dixie, June and Anita...but who knows exactly...this is just my opinion!