Is she interested again? Why the change of heart if she is?

well, as I always say...an ex is an ex for a REASON!! I don't think you should move backwards. Whatever the issue was that broke you up in the first place didn't just magically disappear. She sounds like one of those girls who loves a challenge. Knowing that you were completely free and single didn't spark her interest, but one mention of you dating somebody else and she calls you right up? Stay away from this one.....whether she wants you back or not, she will end up hurting you. Don't buy into it. just stick to trying the "friends" thing. trust me....she's bad news and it is ALWAYS a mistake to try re-connecting with an ex. good luck to ya love.