There’s a reason Water for Elephants is considered a modern classic by many people: the setting is vivid, the story grabs you, and the characters are compelling. What more can you ask for period fiction?
Look, there are lots of gay relationships that are unhealthy, destructive, and sinful. But guess what? There are also a ton of straight relationships that are unhealthy, destructive, and sinful. Neither has anything to do with the orientation of the partners. Rather, it has everything to do with how those partners treat one another and how they care for that relationship.