Maybe Someday by Colleen Hoover

Nominee for Goodreads award in 2014 Twenty-two years old, Sydney’s life is perfect. College, steady job, wonderful boyfriend-Hunter, best friend/roomie - Tori.  But things change when she discovers Hunter is cheating on her!  Her mysterious neighbor Ridge catches her attention and she cannot take her eyes off him or stop listening to the passionate way he plays his guitar every evening out on his balcony. And there's something about Sydney that Ridge can't ignore, either. When their inevitable encounter happens, they soon find themselves needing each other in more ways than one... What would Sydney do?