We write a lot about Maslow's hierarchy of needs on this site, as it's definitely a guiding principle in the way we view the world and the way we approach therapy. Sex is a basic human need, and without a healthy outlet for sexual expression (and all the other drives we humans are compelled to act on), we'll never really be fully self-actualized, that is- just feeling okay in our own skins.
In the Hierarchy of Needs, we have drives for sex as well as intimacy, belongingness and love - but they are not at all the same level. Sex is at the very bottom, like eating, drinking and breathing. Feeling desire and feeling compelled to act on that is not an addiction or a sin - it is a basic human drive. How you relate to others sexually, and what emotions may or may not be tied to sex are higher up in the hierarchy and are considered "higher order" needs/drives.
When we are bombarded with messages about masturbation, fantasy and sex being addictive and are taught only about abstaining from sex to prevent the inevitable STD's and pregnancies that accompany sex, this leads to a block in a fundamental part of who we are as humans. If you feel conflicted about masturbation or consensual sexual expression and activity, it will absolutely prevent you from having healthy outlets in the rest of those higher order areas.
It's common that a first part of sex therapy begins with Permission- permission to be sexual, and permission to be human.
MyTherapist New York offers sex therapy and counseling in Manhattan