you certainly don't need a partner to be happy, but loneliness is a bitch
that said, a partner isn't the only way you can acquire intimacy either; even a platonic relationship can be just as fulfilling if not more, if it's agreed upon to be so
happiness is a not a goal or destination, it's a system that you refine over and over to increase the frequency of feeling happy
and hint: it doesn't involve romance/sex