My wife and I were both open about ours, and being open about it made trusting easier. I’m not sure who would have an problem knowing approximate numbers unless they have jealousy issues or are judgy.
Because some people like to use it as a bludgeon (or get jealous, as you say). After a couple of those, I decided not talking about it was best and that someone really NEEDING to know/talk about it is actually a red flag.