if we take Paul out of the equation for a minute, if that doesnt seem to heretical,(I nearly said 'peace be upon him') how many references to sex would there be in the New Testament then?
I think its important to remember that, however essential Paul might have been to the foundation of the early church, he was only one man and afflicted with blind spots and obsessions like the rest of us.
It's also important to remember that the culture in which the early Christians were living was an unusually promiscuous one. This more than accounts for Paul's special condemnation of it.
The other thing to remember is that Paul never expected his letters to made a part of the bible. They were written with particular people, and particular problems in mind. I fully accept that they are spiritually inspired and have a lot to teach us even today but no document should ever be read or interpreted without bearing both context and the writer's intentions in mind.