Ok well basically there was this girl who I kind of liked and she liked me. We were not going out! Even though we both wanted to. When I asked her out she turned me down because her ex-bf had asked her to take him back and she said yes. She told me she "loves" him then I asked out her best-friend. Was I unfaithful?

Unfaithful how?

No.

No!! You can't be unfaithful to someone that has rejected you.

Not at all... ease your mind. You were not dating this girl and she has a boyfriend. You are free to date whomever you like.