I don't know.
What's the real reason why people have one night stands?
There are lots of reasons. For some it is because they, at least temporarily, feel wanted. For others it is the high of sex and/or the thrill of danger being with someone they don't know. For some it is just a bad decision, or maybe not even a conscious decision, that has been fogged by drugs/alcohol. For some it is because they want sex but not a relationship.
Assuming this link is intact, you can download a power-point presentation that studied your question from cornell university that is pretty interesting:
