Jacked and Jaded by Shay Michaelson

Jackson met Calliope when she moved into the house across the street from his parents. He’d thought she was the prettiest thing he’d ever seen, until he found out she was sixteen years old—cue the sound of screeching tires. He immediately put her in the friends only column and that’s where he continued to keep her for four more years.
One night she catches him home alone. He’d been drinking or he’d never had let things go as far as they did. In a weak moment, he takes her to bed, only to wake up the next morning telling her it never should have happened and it was a mistake, despite the fact she was now twenty years old. Immediately, he sees he’s broken her heart, but he couldn’t help it. There was eight years between then and he just couldn’t get over that fact.
Thanks to his unkind words and actions, Calliope gives up and moves to Boulder. At first, he thought it was for the best. It would be good for her to date guys closer to her own age. Then he gets a phone call saying she’s been in an accident and is in the hospital. He rushes to her side and quickly sees how his hang-ups have affected her.
Realizing he could have lost her forever, he decides he doesn’t want to live his life without her any longer. He’s going to claim her as his, even if he has to fight Calliope herself. He only hopes that the one thing he’s been keeping from her doesn’t push her away forever.