It isn't that they want to announce it it is that they have to keep it secret in every single other part of their life. Can't sleep around without fear of it being leaked, can't get close enough to anyone to have a meaningful relationship without it getting found out, if they do can't go out with their partner wihtout the media being suspicious, can't go on holiday with their partner etc.
Having to keep such a huge part of your life secret from everyone must put a huge strain on everything.