My friend,
Happiness is elusive. Perhaps it proves that it is relative, or perhaps it is just abstract, perhaps concrete only in the eyes of the beholder. As such, it is like beauty: it is in reality, relative, and yet we as society have come to construct ideals that are so profound in our cultures they feel concrete, as if they went beyond being a construct. Perhaps happiness is like that: perhaps Spartans did indeed find true happiness in warfare, at least those of them who embraced their culture.
But happiness it is relative. And there are those who may be lucky enough to find happiness in the simplest things. Diogenes enjoyed his life in complete dispossession. Lao-Tze could find happiness even in the simplest of things. This are perhaps the opposite of examples that may prove your point, but I try to prove how happiness may be such a relative thing.
Beyond all of this, all I can tell you is that as happiness is relative, no one can tell you where you may find happiness... or not. Yes, many believe that in family one may find happiness, but this doesn't have to be true for you.
As for my own opinion: I am 27 years-old. I am a virgin. I have been in love, or perhaps merely hooked, but never in a relationship, never been mutual. And obviously, no children. And I think that won't change. I have sexual appetite, that isn't it, but still... I feel as you describe, a relationship, is only having someone else to have to hold together, and perhaps this is good, since she may help me as much as I help her, but... well, dunno, under our modern circumstances, I am thankful for not being like that.
As for children? I refuse to have them, even on moral grounds: we are too many. We need to stop reproducing. No, I do not want humanity to go extinct, as some more extreme radicals argue for. But certainly I want population growth to stop. We need to stop, at least for now. Let technology, economy and industry continue it's course in becoming bigger, greater, more efficient and more productive, and let's see if we can expand the surplus in the future to sustain bigger populations, rather than force our economies to run behind us, to chase the endless population growth in a desperate attempt to keep us all fed.
It is okay my friend, if you don't find happiness the ways other's do. What matters most, is that you do find happiness, in your own way, and that may this way you find to also give happiness to others.