Happiness is a choice...so you will either choose it or not, regardless of having sex. Sex isn't the key to happiness (it's simply a pleasurable activity).
Whatever your life is, is what is "normal" for you. That has nothing to do with what other people do...there's a difference between "normal" and "typical". Typically, most people choose to have relationships that involve sex at some point. However, there is nothing wrong with those who don't desire sex and never have it.