His Insignificant Other — Karen V. Siplin

Twenty-nine-year-old New York City film professor Casey Beck is at a crossroads. Employed but unfulfilled, she sees her professional aspirations slipping away. And the personal life she thought was finally coming together almost fell apart when she discovered that her man, John Paul, cheated with his sexy ex, Mali. He swears it meant nothing, but it meant plenty to Casey--and months later, it still does. Casey has tried everything from celibacy to candlelight dinners to get her feelings back on track, but it's just not that simple...
Former dancer Mali always seemed prettier, smarter, and more sophisticated. But the night she shows up with no job--and no place to crash but Casey's--it's clear that she's also nervier. If there's one thing Casey knows, it's that she'll do whatever it takes to prevent Mali from staying with her only other friend in town: John Paul. And Mali knows it, too. As the unlikely roommates' predicament gets thorny and the sexual politics within their tight group of mutual friends gets heated, Casey learns just how far she's willing to go to hold onto a man--and a dream...