I was with someone today and we were talking about a woman, and she said:
"Wow, the husband must be so proud."
I was confused as to which was correct or more appropriate as opposed to:
"Wow, her husband must be so proud."
Both are grammatically correct. "The" is much less common and might have a negative connotation based on "the wife." However, the somewhat condescending "the wife" or "the husband" seems to be used in place of "my wife" or "my husband," which is different from the example you heard, where "the" is replacing "her."
Both are valid, but would be used in slightly different contexts. The normal usage of determiners governs the choice here.
You use 'the' to signify that the determiner phrase refers to a referent already in scope. In this case, if the husband was mentioned previously (perhaps as part of a family), using the is fine:
In this case "the husband" and "the wife" are in scope, since they constitute the "couple* mentioned.
If the referent is not in scope, you should use a different determiner to specify which husband you're talking about. So
Since "Alice" has been mentioned, the possessive determiner her suffices.
There are some cases where you can refer to family members with the without their being explicitly mentioned. For example, "the kids" is normally understood to refer to the speaker's own children. As others mentioned, "the wife" (or "the husband) can refer to one's spouse; this usage is condescending to the spouse.
It can be said both ways.
Let me give you an example:
But you can also say it this way:
That sentence is just as correct as this: