I'm in a relationship but I like another girl?

You have that feeling of what if. Really the only way to get that feeling out of your head is to really do it. Like break up with your girlfriend and go with that other girl you also have feelings for. If it doesnt work out then that feeling of what if she dissapear. But only go out with this girl once you and your girlfriend have a real break up. Your current girlfriend is right though...(last sentence)