I'm living without right now, and it's hell on Earth. So I CAN live without it, just not happily.
But at the same time if I married someone and really loved them, but something then happened where she could never physically have sex again, I wouldn't leave her over that. I could live with love without sex; I'm not saying I'd prefer it, but if forced into it I could cope. However, if she simply decided she never wanted sex again, then I'd leave for sure.
So yeah, sex is real important to me.