The DSM-V is the next (fifth) edition of the American Psychiatric Association's (APA) Diagnostic and Statistical Manual of Mental Disorders (DSM), commonly called DSM-5. It is currently in consultation, planning and preparation and is due for publication in May 2013, when it will supersede the DSM-IV which was last revised in 2000.
Many of us in the sex-positive movement have been very concerned about this issue because we envision great potential for misdiagnosis based on a desire for multi-partner relationships. Adding sex addiction to the DSM-5 as a distinct disorder separate from obsessive-compulsive disorder is highly controversial and the subject of much heated debate.
We polyamorists have a vested interest in this issue because biased and/or uninformed mental health care professionals have been known to pathologize our desire for more than one partner - hence the great demand for poly-friendly therapists. So the criteria for diagnosis matters - a lot. Poly people with misgivings about their choices are particularly vulnerable to misdiagnosis.
So below is the proposed addition to the DSM-5, Hypersexual Disorder. It's better than it could have been, and it's still under discussion, but this is an important step in that it reveals the direction the APA is taking. Note that "Sexual Behavior with Consenting Adults" is listed as one of the behaviors that should be specified in a diagnosis if it exists.
Much more remains to be seen on this. The good news is that this proposal doesn't classify hypersexual behavior as an addiction per se. Were that the case, then poly relationships could be further stygmatized simply because one's partnerships aren't working and the resulting drama is making them unmanageable. (The basic determining factor as to whether one is an addict is whether one's life has become unmanageable as a result of the addictive behavior.)
Hypersexual Disorder 
A. Over a period of at least six months, recurrent and intense sexual fantasies, sexual urges, and sexual behavior in association with four or more of the following five criteria:
(1) A great deal of time is consumed by sexual fantasies and urges, and by planning for and engaging in sexual behavior. 
(2) Repetitively engaging in these sexual fantasies, urges, and behavior in response to dysphoric mood states (e.g., anxiety, depression, boredom, irritability). 
(3) Repetitively engaging in sexual fantasies, urges, and behavior in response to stressful life events. 
(4) Repetitive but unsuccessful efforts to control or significantly reduce these sexual fantasies, urges, and behavior. 
(5) Repetitively engaging in sexual behavior while disregarding the risk for physical or emotional harm to self or others. 
B. There is clinically significant personal distress or impairment in social, occupational or other important areas of functioning associated with the frequency and intensity of these sexual fantasies, urges, and behavior. 
C. These sexual fantasies, urges, and behavior are not due to the direct physiological effect of an exogenous substance (e.g., a drug of abuse or a medication). 
Specify if: 
Sexual Behavior With Consenting Adults