Gillian Anderson's Boyfriend gets Handsy on Steamy Italian Vacation

Gillian Anderson's got another partner opening her files these days ... and sorry, Mulder, these 'X-Files' are strictly boyfriend privileges.

Scully and her bf, Peter Morgan, got steamy sitting poolside in Portofino. She showed off her hard bod in a blue bikini ... which Peter seemed to be fully enjoying. Smart and lucky man.

48-year-old Gillian's moved on from her 'X-Files' days, and now stars on the Starz series "American Gods."

They might wanna rework that title ... "American Goddess" feels a little more appropriate.