His Heart by Claire Kingsley

Brooke Summerlin’s life is like a Cinderella story. Raised by an abusive, drug addicted mother, she desperately hides the truth about where she comes from. But Prince Charming arrives in the form of Liam, the most popular guy at school. He sweeps into her life and carries her away to what is supposed to be a happily ever after.
Until it isn’t.
Sebastian McKinney is the son of an Iowa state champion wrestler, and that’s what he’s going to be. Wrestling is his life. He’s focused. Determined. Nothing will stand in his way.
Except a silent illness that almost kills him.
Brooke’s greatest tragedy becomes Sebastian’s second chance at life. Four years later, he’s moving forward, his body healthy, while she is left to sink in grief that threatens to drown her. Haunted by a past she can’t escape.
But sometimes love transcends the boundaries of life and death—between what is known and what cannot be explained. The heart that loved Brooke continues to beat, and even now, it still beats for her.