My GF says she has cut off her "friends with benefits", believe her?

I think she's still doing it and she is the wrong woman for you to be in a serious relationship with. I would suggest not being girlfriend and boyfriend...just be another Friend with Benifits until you find the right girl. That way you are still single but have the opportunity to get it on once in a while, and since she's not committed she won't technically be cheating...just "slutting" around.