Sex is just not important, except for reproduction.  For men, it's an urge not unlike hunger that prefers to be satisfied but can also be repressed at will.  As a young, single man, sex for me was recreation, and many nights I set out with the other guys to get laid.  That all changed when I decided to get married, and while my desire for sex didn't subside, its importance did, replaced by really important things in life.

If people weren't so programmed to believe that sex is important (it's all over the entertainment media), there would be a lot less of it, and less adultery and spread of STDs.  The lack of importance of sex in my marriage helps stabilize it: no worries about temptation from 3rd parties.