You cannot really tell if someone has connected to a SharePoint from your computer unless you can see it from Web Browser history, or perhaps from a firewall log. However, I don't think many home computers have firewalls that log permitted connections, only blocked connections.
SharePoint is effectively a "web site" that is accessed using web browser or dedicated software (Microsoft Office clients for example) that accesses SharePoint over the net (local or internet) so there are no programs running on your machine that would indicate that someone has connected to SharePoint at some point.