Sounds similar to the same deal I'm in.
I was sorta seeing this girl for a while (we were friends for years before this), and after giving blatant signals (that just about everyone I know took as a green light), and even telling one of my friends flat out that she wanted to have sex with me, she flaked. We were drunk, fooling around, and before things got too fun she went cold and rambled on for a half hour about the reasons why we shouldn't do the ol' in out.
Such examples as:
"We've known each other for too long"
"I'm attracted to your personality, but I don't think we're sexually compatible"
"If we fvck, you're gonna want to be in a relationship" (this I think was the strongest reason, and my thinking is that SHE'S the one who might want a relationship in the end, but she's too concerned with some schooling she's got coming up, of which she never shut the fvck up about!)
"This is too awkward"
"I like hanging out with you, and I don't want to screw that up"
Blah blah blah... who gives a sh!t?
I told her, "Fine, we can still be friends", even though I had zero intention of ever talking to her again.
A few days later I get a text message asking me if I was going out to the pub that night. I, already planning to go there with my roommates responded with a yes. To this she told me that I didn't have to come out on her behalf. The nerve of some people.
After I get there she tells me that she felt "dissed" that I went off to a table with my roommates and not her. Then she asked me what time I was gonna pick her up next week to go to this concert. I dodged the subject.
Later on I finally get it out of her that right before we started hanging out as "more that friends", she had sex with this one particular lowlife. This is the type of person who never shuts up about his drug connections, how much money he makes, how high he got over the weekend, how awesome he thinks he is, his bad tattoos, ect..., but I always had fun calling his bullsh!t and making him look even dumber in front of everybody.
Anyway, I about blew a gasket. She essentially took my manhood, held in in her hand, and smashed it with a well timed strike of a sledgehammer. Thanks for telling me that I'm not "worthy" of you, but this douchebag is more than good enough. It sickens me to think my mouth touched hers, probably only days after hers lips had been.... I don't even want to think about it. Kunt.
her: Are you mad.
evoke: Of course not.
Now, the classy thing for me have done right there was to excuse myself to the bathroom, and not come back, but I still had a few hours of drinking left in me.
She eventually left, and after a few more rounds, I took out my cellphone and started typing up something. Something to effect of, "I think your standards suck. Good luck with school. Goodbye.".
She responded at first with an "I don't understand" SMS, followed by a phonecall (I didn't answer), followed by an angry rant about how I shouldn't judge her (but it's ok for her to judge me?), followed by some more unaswered phonecalls.
I sat and drank my beer, content.
Last night my one roommates' girlfriend ran into her at some bar. She told her what had happened (The "I just wanted to be friends" deal), and then went on about my good qualities for a good hour. If she thinks so highly of me, why couldn't she just give me what I wanted? It's not like I wanted to sever the line between her and me, but she pushed those pins a little too far.
To this my friends GF responded with "It sounds like you lead him on. I would have done the same thing if I were him.".
I hope she gets it through her head that it's not cool to fvck about with a person's feelings. I know one of her ex's, and he's a lunatic of her creation. He still thinks the two of them will get back together, and she eggs him on by calling him up to ask quick questions every couple of months. Just to make sure she stays in his mind.
The moral, stick those attention wh0res as quickly as possible, run, and don't look back.
