Sounds like she's confused sex and love. That happens alot. Sex changes things and many confuse that for love. It's the bond created by the intimacy that it creates. She may honestly think "this is love". But then time passes that that feeling (or bond) lessens and she turns her attention elsewhere. At sometime in her life she will realize that what she sees as love isn't love at all.
As for the behavior when drunk, that's the nature of alcohol. It takes away the inhabitions. While she wouldn't look for a booty call sober that "need" takes over when she's drunk. It's simply what alcohol does to our brains. And it's always possible that her actions are covering up problems (like self esteem) that she isn't comfortable facing. I know that's how it goes with my older brother.