What is the ruling on my telling my wife: "If I see you smoking a shisha, you must leave the house and have no place in it"?

You have not specified the exact wording of your oath. If you did not see your wife drink what you warned her against, then there is nothing upon you. And if you saw her consuming the drink and you expelled her from the house, then nothing is incumbent upon you.

However, if she remained in the house after you saw her drinking: - If the oath was by divorce: Divorce occurs according to the majority of scholars, and this is the most valid opinion. Ibn Taymiyyah holds that an expiation for an oath (kaffarat yamin) is required if you did not intend divorce. It is safer to follow the opinion of the majority. - If the oath was by one of the names of Allah: An expiation for an oath (kaffarat yamin) is incumbent upon you.

Swearing by divorce is not legislated, and excessive swearing by Allah is not recommended.