What is the best way to cut a friend-girl out of your life to protect your relationship with your girlfriend?

[Brian Jones]

I am thinking about changing my number so they don't text me. They are also on my facebook and myspace. I recently got the inkling they like me and it is making things difficult because my girlfriend sees it too, even though my friend is making herself seem supportive. In fact, I use to confide in her about my girlfriend before we became serious. Should I give this friend an explanation that I need to cut friend-girls out? She is on my facebook & myspace too leaving tons of comments.