Hmm...well sounds like you have already messed up by letting her know that you don't like the guy. Shows her that your insecure and she is feeding off that whether she knows it or not. You need to turn that back around by just not giving a f*** about it. 1 rule that has never failed me in my entire life, whoever cares the least always wins. I'm sure some will try to flame me for that, but it's the truth.