What's sauce for the goose (is sauce for the gander).
(British, American & Australian old-fashioned) alsoWhat's good for the goose (is good for the gander). (American & Australian old-fashioned)
something that you say to suggest that if a particular type of behaviour is acceptable for one person, it should also be acceptable for another person If your husband can go out with his friends, then surely you can go out with yours. What's sauce for the goose is sauce for the gander.