I am pretty sure you have been thrown up against the fake boyfriend. If the girl really showed the attraction that you previously mentioned, she either doesn't have a boyfriend, or she is looking to trade up. You need to not show any signs that you were put off by the 'boyfriend'. Play normal game. If she brings up the boyfriend again, I suggest Adonis's method of dealing with it. Look up the strawman method, on the forum here. I posted about it before, and I think other's probably have to. Don't fall for the mythical boyfriend. The worst thing that can happen is that she totally blows you off. I think she was probably a little put off by the previous decoy blow off and now she is testing your meddle to see what type of guy you really are. If she starts to really blow you off, neg her a little or, turn away and talk to someone else. You most likely showed too much interest earlier, at one point. So you need to counter that by being a little dismissive when she starts to be defensive. She needs to be chasing you.