So glad this tune was requested.
It's a little-known fact (maybe only to my generation), but this awesome fretless playing is courtesy of none other than Pino Palladino, of John Mayer and D'Angelo fame. I guess in the 80s he was just hanging out in the studio nailing sweet sweet fretless lines on pop ballads. Quintessential 80s fretless tone. Sorry I don't have a fretless to help recreate it, but at least we have the lines here to enjoy.
Have a great weekend, all!