My problem: I fell for one girl, stopped talking to her, and I'm now dating someone else. Except I still feel something for that first girl. I love my girlfriend, don't get me wrong, I love her now and forever, but a little piece of my heart is still with that first girl. But, I love my girlfriend more, and so I can deal with it.
That's all you gotta do - figure out which one you love more. Because the second person, the one you've just fallen in love with, could be your soulmate. Don't miss the opportunity. The person you're dating should understand.