Barring physical and mental illness, disability, and other extremes like loss/grief/high stress.
I.e. in regular, healthy relationships, both happy and fairly young, do you owe sex to your partner? I'm not talking every day, or even every other day.
How many times does 'I'm tired' or 'I'm not in the mood' fly before you just get pissed off with never being approached for intimacy, straight up rejected, and made to feel like a sex pest for wanting physical contact with your life partner?
I hope no one insinuates I am referring to being forced to have sex/rape, because that just isn't the case. I would never force anyone to do anything they don't want to, especially intercourse, but I can't help but shake the feeling that OK we might not all be ravenous for sex all the time, but even if you can't really be arsed, do you see sex as sort of a duty to your partner?