people in the notes of that porn addiction post like "i've had men jerk off to porn when i was right here being sexually available" and beyond the idea that not wanting to have sex is some sort of pathology (bad), like... do you really not understand the difference between sex and masturbation?
sex is a social action, doing it means you are taking the needs, desires, and wellbeing of the person you're fucking into account. it takes a certain amount of mental energy and a certain mood to do that? pulling up xhamster and cranking it is like, using similar body parts, but its a completely different task.
if you're with a guy and you're expecting sex with him to be basically him masturbating with your body, well... that's something that needs to be specified and negotiated ahead of time, not the default assumption for sex.