For example, guy and girl go out to dinner, have a great time, have a couple of glasses of wine. Girl goes back to guy's apartment; they are both light-headed, and end up having sex. Months later, after a breakup, the girl legitimately believes she was taken advantage of ('The asshole was using me all along; he plied me with wine and raped me'), while the guy legitimately believes that what happened was 100% consensual. It is obvious why after a tough break-up the girl may (choose to?) think this way. Also, she IS on some level right: the guy DID want to have sex with her, and the dinner and wine weren't a completely innocent gesture. But guess what: this is what relationships are like, and these situations are virtually impossible to avoid. Every relationship I've been in has had similar 'open to interpretation' moments.
Anyway, this is one reason why relationships today are sometimes an absolute hell; we live in a culture that encourages us to treat everything as means rather than end, including people, and at the same time we are obsessed with ourselves--obsessed with protecting our beautiful, world-deserving self, and are terrified that we might be being used, or that we might be using or accused of using others.