Unsubscribe

There is no way for a user to delete their own record.

What I suggest you do it create a checkbox field that tells you whether the person is subscribed or not. They can go to their record edit page and uncheck that. You could use the state of that field to filter your list so you would be showing only records that are subscribed.

Periodically, an admin would have to go in and delete all the records that have this unchecked if you want to delete those records.