He’s A Mean One by Lani Lynn Vale

For a solid five years, Jasper Madden has done nothing but look the other way when it comes to Calliope Hodges. At first, she was way too young for him, barely eighteen the first time he laid eyes on her. It also didn’t help that he’d witnessed her at the lowest of lows, practically making peace with rock bottom.
But as time goes by, he realizes that Calliope is different. She’s a brave, stunning young woman that has slowly captured his heart while he was watching from the shadows.
He knows that it’ll take time for her to realize that he’s not the enemy, but instead her saving grace. So he decides to play the long game.
For years, he’s waited in the periphery for her to be ready. He stands right there, knowing that one day she’ll look up and finally see him as the man that is desperately in love with her.