People who leave a long term relationship and jump straight into a new one have issues. Do you have a fear of being alone? Why do you think you cant leave unless you have someone else to run to? Why not take some time out to be alone first instead of making rash, impulsive decisions based on mere infatuation?
Were you unhappy with your partner before starting your emotional affair and thinking of leaving or is this just you thinking the grass is greener based on some butterflies?
Look up the 9 stages of love. Youve likely gone through them all with your partner and now you are about to trade her in (probably the love of your life) for a what if.
I think you will regret it and want to run back to your gf in about 2 months but you cant do that so when you make your decision-make sure you are willing to face the consequences. There is no going back. She deserves better than being a backup a plan and I just hope she knows that
"Don't ask a question if you can't handle the answer".