Firstly, it's not an affliction, just like how being straight or being allosexual isn't an affliction.
Secondly, rarely does a sex scene move the plot forward.
Thirdly, less is still more.
Fourthly, sex scenes still don't help procreation one bit, now does it? So you didn't answer my question, but I'm no longer interested in your answer. By calling me an affliction makes it perfectly clear to me that what you have to say isn't interesting.