In the list of households everyone in the household will be listed under the "household" name as defined by the field of the same name.
But if you go into the household, I think you'll see her with her own name. If not, double check the marriage information on the husband's record. That's where the information is coming from - NOT from any non-member record you might have created in MLS.
At least that's the way it normally works. Since she's a non-member, I'm not sure as there is a way to indicate that she hasn't taken her husband's name. The info on the marriage is always the maiden name.
You could call Local Unit Support and see if they have any tricks on their end. The whole display of non-member spouses is outside of the control of MLS.
Have you searched the
Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.
So we can better help you, please edit your
Profile to include your general location.