What do you call a woman that dates a married man?

mistress. noun. a woman who is having a sexual relationship with a married man.

Can I be a Mrs without getting married?

If youre only inviting a woman, and shes married, use Mrs. When inviting an unmarried adult woman, or if youre not sure if shes married, use Ms. When addressing an invite to an unmarried couple, write the mans name first, followed by the womans (Mr. John Smith and Ms.