You reply to the forum. This sometimes creates a little confusion but that only increases the fun ;-).
In special incidence I have contacted the individual person, but that is only in very special cases.
As a rule I do not copy and paste into the Notes field. Especially text from an HTML document with text.
Marriage notes can be access to change or to be added to from People, Person. Highlight the fact in the Individual & Shared Facts. Go to the right pane, below the facts statistics, you will see Fact, Sources, Notes. Click Notes to see the information in the Note.
Normally just deleting the person should not cause a problem, but you were trouble shooting a problem. My terminology was incorrect what I should have said was go to People, Person, and highlight the person you want to "disconnect" Click Person in the Menu File,Edit, View, Person, and select Attach/Detach Person.
As I said since you had a problem there is no need to compound a problem by deleting the person attached to the tree. The problem you are troubleshooting may have been caused by the attachment links of that person. If this was the problem deleting without detaching may have compounded the problem.