Heterosexual sex isn't illegal, considered vile by society, mark you on online registries, prevent you from living in many places[1] or require preying and possibly kidnapping to accomplish. There are many reasons why a pedophile would watch CP but not actually attempt anything.
I'm sure there is a correlation, but I'd want evidence that it is high.
There's probably an excellent correlation between viewing porn involve heterosexual adults and people who engage in heterosexual sex.