The department that sends the emails is not allowed to know whether or not you filed a tax return with a different account or with your spouse. Sounds weird, but it's part of taxpayer privacy. If you filed a joint return with your spouse, you should use that account going forward. You can unsubscribe to emails related to your old account, if you like. You may also want to download and save archival copies of the last 3 years worth of single tax returns (download the pdf of "all forms and worksheets" and save it in a safe place.)
