I've never had a long-term very close friend in a non-romantic sort of way who didn't drive me up the wall from time to time. I think that in a romantic relationship you have to weigh what you have, pros and cons against what you're potentially missing out on by being comitted.
For me, I wouldn't want to be with anyone else. Sometimes he's a huge pain in the ass, but he's MY pain in the ass. lol It's unconditional. I don't just quit on the whole deal because he had a crappy day and isn't up for listening to me chatter about whatever. Nor does he just say "screw this" when I'm moody and less than a peach. It's give and take. But we're an awesome match.
I don't think every moment has to be buttercups and giggles, but there's no reason for anyone to tolerate mistreatment or unhappiness. Life's too short to be tied to someone who's holding you back. I think a good relationship is a partnership-- you are going in the same general direction in life, sometimes side by side and sometimes helping the other along.