Many others have said that, although in Real Life, it's harder to tell.
However, in the interests of science, can you explain how a man who can't have an erection could be said to be in physical need of sexual relief?
Can’t a guy have a need for sex that isn’t physical? Like a woman?
Would you tell an asthma sufferer who is having an episode where she can't breathe, that this proves that she doesn't need to breathe? As an admittedly "over the top" example, it illustrates a case where one part of your body is sending screaming signals that you should perform an action, while the part that actually needs to perform the action is not working
It's one of those things you may need to be a guy to understand.