Sexual energy is important, and very important for life, as it's directly linked to the creative life force.
You don't need to have a sex partner for that though, you can channel creative life force and sexual energy in other ways. And you can entertain yourself as well.
Suppressing sexual energy is very unhealthy and can create serious (health) problems as a result if it goes on too long.
This has nothing to do with sex-addiction, mind you. I'm talking about healthy, normal sexual energy.

Many people do have issues concerning sexuality as this has been an issue for thousands of years which results in excessive drive or abnormal behaviour in some, or lack of drive.

So yes it is very important, but not in the sense you need to have sex with someone regardless.