It depends on what you mean by "revealing your sexuality". If, say, at some work-related party, a woman introduced her husband or boyfriend or fiancee or male partner, then that would be implicitly "revealing your sexuality", would it not? Likewise introducing her female partner as a +1 would show her to be at the very least bisexual, even if it was never discussed some other way.
Or maybe it was found out inadvertently, because some other colleague saw you and your partner, and it became pretty obvious that you weren't just friends with this other person.
At any rate, it's obvious that you don't have to explicitly shout out loud that you are gay or hetero or whatever in order for that information to become known just through normal conversation, or normal social interactions, or whatever. In most cases no-one will care, of course, but when it does you would be pretty upset if the knowledge that you were gay was enough to cause your employer to fire you, to the point where you would have to take active steps to hide your sexuality, rather than just not really talking about it much.