I'm going to keep part of a bonus for myself without telling my wife.
What Is the reason for keeping part of the bonus for yourself and hiding that fact?
I don't need to explain my reasons for this. It is something I need to do.
Your partner has a right to know about your bonus compensation and hiding it from her is improper. If you keep secrets from her, it will lead to distrust in the relationship.
What garbage, can you say anything else.
It's hard to refute your reasons when you won't state them. At any rate, keeping things hidden from your wife is generally a bad idea.