It's Not Me, It's You by Stephanie Kate Strohm
Avery Dennis is a high school senior and one of the most popular girls in her class. But a major public breakup with her boyfriend threatens to ruin Avery's plans for a perfect senior prom and Avery starts thinking about all the guys she's dated. How come none of those relationships worked out? Could it be her fault? Avery tracks down her exes and interviews them, compiling a total account of her dating history. She discovers some truths about herself along the way...just in time for prom night!