Sooooo your thinking of going back to a girl who left you for no reason at all :/
Your stupid to even think about it......i can tell you now your as bad as each other.
It just what happens you think you love her but you don't just sexual lust for something you once had >_>
Go back to it going to end again and hurt once more.
Your current GF sounds like it was a bit rushed and you wanted somebody after GF 1 so did not think about it. Again just lust....and your bit lost as to what love is. Don't worry we all like it
I would talk to your current GF and say you love her no matter how many girls you talk to your not moving to the next one.
May be wrong about the current GF and it may be love after all.
I would stuck to the one you have right now the other one made the mistake letting you go.