Detective book:
Grizzled detective struggles with demons and alcoholism and his wife and kid hate him. He gets assigned to a serial killer case, and a young female detective is assigned as his partner, over his objections. He struggles with his demons and solves the case; during the investigation the young detective is either killed or he bangs her, or both. He achieves some level or other of spiritual solace but his wife and kid still hate him. He throws his badge in the river.
Bookman