girlfriend (or woman with whom one is in love or has an intimate relationship) n.: inamorata
One of the few people who was close to both of the Waleses, Hoare invited [Prince] Charles and his inamorata Camilla Parker Bowles to discreet dinners at his home and served as an ad hoc counselor for [Princess Diana]. (Michelle Green, “A Princess in Peril—Accused of Harassing a Married Friend with Silent Phone Calls, a Troubled Diana Seems to Be Spinning Out of Control,” People, 9/5/1994, p. 70.)
