We once again meet our refrain warning the daughters of Jerusalem. If you've read my comments closely you should be able to determine two opinions that I have. One is that the couple is not married in any of the scenes discussed so far. The second is that I believe they have been sexually active in some way shape or form. While we should not assume that Israelite culture was anywhere near as "conservative" as the legal portions of the Torah might suggest, it would be surprising to find a work in the Old Testament unabashedly extolling sexual love between two unmarried people. And allegorical interpretation wouldn't solve that problem. Even if it did, most scholars hold that allegorical interpretation arose because of the Song was in the canon, not the other way around. How did it get there?
Perhaps the Song is ironic. Perhaps the Song is a warning against what it seems to be celebrating. Specifically, it could be a well crafted warning to women to be careful not to fall in love before the appropriate time. Several factors lead me to this possible identification. First, the Song was associated with Solomon, which means that it was associated with the ancient Israelite wisdom tradition. This implies a clear didactic concern. When we scan the song for signals as to this concern, we run across one sentence that repeats. 'I adjure you daughters of Jerusalem...do not stir up or awaken love until it is ready!' This is the overt moral message of the song. Each occurrence of this refrain follows a section describing intimate activity or that has strong sexual overtones. Second the woman's behavior in the song is sometimes outrageous. For example, her wandering out at night in search of her beloved is extreme behavior. By portraying her as being wild and throwing caution and social mores to the wind it warns others to guard themselves or they may be transformed into a wild woman (and perhaps this explains the bizarre scene in chapter 5 where she gets beaten by the guards). This also, in my opinion, explains the female-centric voice of the poem.
Who would have interest in this type of text? Older, elite, male, religious leaders would certainly be one group. They would have a strong interest in seeing their daughters remain chaste. It also would cause the text to cohere with portions of the legal code about premarital sex, even in terms of their strong focus on the activity of the woman.
I certainly don't think it's an open and shut case, but I would want to submit it for further thought. I know I'm swimming against the tide with this suggestion, but I just don't see how the Song could get canonized otherwise, if it is a poem about premarital sexual love.
 A point held by most commentators, including at least one conservative scholar - Tremper Longman.
 Interest is not being used as a loaded term here. Some of those interests that drove the canonization of the Song were probably positive, and some probably negative.
 Premarital sex isn't a major topic in either the Old or New Testament, so I don't want this sentence to be understood as suggesting that the Bible focuses on the topic a lot. It doesn't. It's not even in the discussion with issues like generosity and the just treatment of the socially disadvantaged. In fact, outside of a couple of texts in the law it'd be hard to find texts that give clear condemnation. The case must be inferred.