What is there to say? Absolutely nothing. Cutting contact, turning around & walking away may make you feel like a dumba$$ but trust me: Creating drama & tension will have an counterproductive effect. You being angry, sad, p!$$ed off or affected in any way, gives her the justification she needs, to choose the other guy over you. No matter what kind of AFC, bum or freak he may be. You cannot win.
Cut contact, see other girls ( as a tipp: girls with higher IL ) and don't mention it to her or any of her friends. Don't let 'em see you sweat. Maybe she'll come around because she feels like she's missing out on something. If not - no big deal.
I had a similiar scenario not too long ago. Although the girl had high IL but I didn't make any moves on her and tried to stall, because I had a lot of other serious stuff going on in my life and the last thing I needed, was a woman. So she started seeing a guy and became more and more unavailable. Although I really got p!ssed off and angry (mostly at myself for whimping out) I completely cut contact. You will feel better in the long run. Actively trying to "turn things around" is an uphill battle. There is practically nothing you can do.
Reminds me of the movie "Swingers" from 1996 and the famous/notorious dialogue:
Mike: Okay, so what if I don't want to give up on her?
Rob: You don't call.
Mike: But you said I don't call if I wanted to give up on her.
Rob: Right.
Mike: So I don't call either way?
Rob: Right.
Mike: So what's the difference?
Rob: There is no difference right now. See, Mike, the only difference between giving up and not giving up is if you take her back when she wants to come back. But you can't do anything to make her want to come back. In fact, you can only do stuff to make her not want to come back.
Mike: So the only difference is if I forget about her or just pretend to forget about her?
Rob: Right.
Mike: Well that sucks.
Rob: Yeah, it sucks.
Mike: So it's just like a retroactive decision, then? I mean I could, like, forget about her and then when she comes back make like I just pretended to forget about her?
Rob: Right. Although probably more likely the opposite.
Mike: What do you mean?
Rob: I mean at first you're going to pretend to forget about her, you'll not call her, I don't know, whatever... but then eventually, you really will forget about her.
Mike: Well what if she comes back first?
Rob: Mmmm... see, that's the thing, is somehow they know not to come back until you really forget.
Mike: There's the rub.
Rob: There's the rub.
