Mi mujer (literal my woman) is also acceptable.
Novia = girlfriend Novio = boyfriend
Esposo is husband (m. spouse) Esposa is wife (f. Spouse) Los esposos (husband and wife)
Marido is husband (married man) Mujer is woman
If you use Esposo, use esposa with it If you use marido, use mujer with it.
Personally speaking to Spanish people, marido and mujer are more frequently used
And also fiancée or bride:
The possessive often comes before the noun (especially if it's a person), where it drops the -a, so mi rather than mía.
Using my wife sounds poetical and it could be used as a vocative*:
- ¿Cómo has dormido, esposa mía?
How have you slept, my wife?
*Vocative: A word used to address a person without it really playing a role in the sentence (it is not the subject, an object, etc.)