I would add, that your fiance's father "granting them access" does not necessarily constitute the legal right for them to use that access forever. As others have said, find out exactly how the access was conveyed. You may not HAVE to provide them any access at all. If the terms of the access are totally undefined, you can deny access or negotiate what you wish to do on your own terms. Mr. Knowitall's first post addresses this; I just thought that the idea may have gotten lost in the subsequent discussions.

