As long as you are not still active on any credit accounts under your married name, I would obtain your credit reports
(if you haven't gotten one in the past year, you can get your reports from all 3 agencies from http://www.annualcreditreport.com ). Once you've obtained the reports, see if your married name still shows as an alias on them. If so, contact each credit reporting agency and request the name be removed as invalid.
In order for this to be succesful, though, you can't have any credit accounts (open or closed) currently reporting on your credit report under your married name. As long as one account is still being reported under your "old" name, the reporting agency will refuse to delete the alias from your credit record.
If you want to stop getting the pre-approved offers only,
you can "opt-out" of prescreened credit offers over the web
at https://www.optoutprescreen.com .