I used sex as an example because it was simple and would convey my point. Other examples would require more specific situations and might speak to less people. Of course it's not specific to sex.
I do think sex is the perfect example because while knowing if your partner is sexually active with other is important for health reasons, it is also a very private and intimate act for most people, during which they make themselves vulnerable and transparent to their partner(s), and might not want details repeated without prior approval.
I think the concept is applicable to other situations, though.