I'm not including this person on my tax return

You can create an entirely new account for your Married Filing Separate return if that is easier for you.

However, you will still need your spouse’s basic information (name, Social Security number, for example) in order to file Married Filing Separate.  The basic information for your spouse is included as part of the heading of your tax return and you will also need to answer some questions regarding your spouse and how their return will be filed.  So, if this is the kind of information that you are still seeing in your return, then that is normal and it should be included.