Is the sex a necessity?

The sex isn't a vital necessity, one example of this is that you can stop to do it, you won't die or become ill.
Exist many people that have a healthy life without have sex.
Is possible to say that have sex is a physical feedback or reaction against the stimulates of enviorment.
Without stimulate, there's not a reaction.
the sex migth become a necessity only if you overuse of it.
In the same way you can depend of alcohol if you don't control the way you drink it.