Dealing with addiction in your life? Check out In the realm of hungry ghosts. There's also an audiobook of this one.
Have unfinished business with those you care about or feeling trapped or stagnant in your relationship? Be brave and read Radical Honesty. Read with caution.
Curious/confused about the evolutionary backing of monogamy? Read Sex at Dawn.
A how-to on a bunch of different sorts of relationships is what The Ethical Slut is all about.