Jason by Laurell K. Hamilton

But sometimes you have to explain the unexplainable, especially if the love of your life needs to understand, or she'll leave you. Jason Schuyler is one of Anita Blake's best friends and favorite werewolves, with benefits. J.J. is his lady love, an old flame from childhood who dances at one of the top ballet companies in New York. She's accomplished, beautiful, and she's crazy about him, too. Neither of them wants to be monogamous, so what could go wrong?

J.J. is enthusiastically bisexual, with an emphasis on the female side of things. She plans to keep sleeping with women, because Jason can't meet that need, just like she can't meet Jason's need for rough sex and bondage. J.J. doesn't understand why Jason isn't content to go elsewhere for a need she can't fulfil, so Jason asks Anita to help him explain.