It's way cheaper and easier to swap jobs vs swap spouse and family. If i have to swap jobs my old job isn't entitled to half my stuff plus a large chunk of my ongoing income. The spouse and family also have access to me at my most vulnerable, while I sleep. If you really think about it my position is the obviously cortect one.

Doubtful. But things like mail, documents, file storage, etc might be another story.

It depends on what the person in question is hosting, and how it relates to the life of the SO. There are a lot of options around, just take a look at the awesome-selfhosted repo on github