Best Kept Secret (Kiss & Tell Book Club #2)
Susan Coventry

Kelsey has been crushing on her brother's best friend/roommate, Hudson, ever since she met him over a year ago. Unfortunately, her brother is vehemently opposed to them dating, warning her that Hudson is a player and she'll only get hurt. But the more he tries to protect her, the more determined she is to prove him wrong.
Hudson has always obeyed the "friend code" which includes not fooling around with his best friend's sister. But the more he gets to know Kelsey, the harder she is to resist. Soon they begin seeing each other secretly; however, Hudson's been keeping an even bigger secret of his own.
During a romantic weekend together, Kelsey discovers the truth from an unlikely source, and suddenly, she understands her brother's warnings. Hurt and angry, she retreats from Hudson, although he's not giving up without a fight.