Huh, so because it's categorized as a "sex act" it must be vital to life? What kind of imperative gives you that idea?You are comparing a sex act to non-sex acts. Itchy nose or computer use is not vital to life.
No it's not, if it is, explain how. A lie of omission is to just not tell someone something.No one said it was. Not telling something and deceiving by omission are two different things.