And you can deny the immorality of making a sex tape all you want, but in this case there are two moral violators.
To use your own words: They are both at fault! Period!
It is not immoral to take videos of your sexcapades if you want to. As long as your intent was to keep those between the two of you, the non-violating participant did nothing wrong.
If you don’t know that, you picked the wrong profession.