You can like watching people/watching porn/whatever and like getting off on it, but you don‘t want to be involved in it yourself because while watching others have fun is fun for you, you don‘t want to actively participate/be involved with them.
It‘s called autochorissexualism and is one type of asexuality.
In the same vein I could ask you: do you watch porn because you fantasize constantly about those people involved? Seems weird to me