The aunt is linked to my grandparents correctly. But the person that was her husband, whom I knew personally during my Aunts life is someone not related to the family.
You are saying that your aunt has the wrong spouse. You can remove/replace him by clicking the Edit pencil, in the marriage box, in the Family Members section. We are enclosing the article directions:
You can correct an incorrect couple relationship at any time. Here are the steps to remove or replace an incorrect spouse.
Tip: removing or replacing an individual's records can feel intimidating. Rest assured that changes can be undone in the Latest Changes feature. It's also helpful to record the ID number so that the removed or replaced person is easy to find later on.
We are also enclosing the URL to the article, in case you need the complete directions.