Hexhunter. Hexworld, #4

Detective Bill Quigley fell in love with the familiar Isaac the night they met. But after more than two years, it's time to admit to himself that Isaac doesn't return his feelings. Isaac knows he's too broken by his experiences for anyone to fall in love with. Especially someone like Bill, who deserves a partner unplagued by Isaac's nightmares and doubts. When children go missing from an orphanage, Bill and Isaac must work together to find them.
And as years of yearning threaten to ignite into passion, they must decide once and for all whether to take a chance on love.