While it’s perfectly normal for boys (and girls) to be interested in sex and even “porn”, one problem with it is the expectations of sex that it presents to young minds. Most women are not playboy material, don’t orgasm every time, or at all, and don’t want to have sex in a tent or bouncing on a trampoline. It’s little wonder so many kids are jaded and disappointed over sex when it’s promoted (mainly) as just recreation with no feelings involved.
For boys, I think Lord Byron's quote:
"Man's love is of man's life a thing apart,
'Tis woman's whole existence."
is on the mark.