The New Testament isn't, but surely the Torah was?

Parts of, yes. There ARE lists, I'll grant you that, but even the Torah must be viewed within the context in which it was given.

And if nobody in Christ's society had sex outside marriage

Ok, I give up on this point! All I was trying to say was that I can easily see the reason for not including explicit instruction about sex outside of marriage. My conviction on this point does not come from direct biblical instruction but rather my interpretation of the principles of marriage.