Welsh-born actor and Richard Burton's first wife, she moved to the US after their split and co-founded a famous New York disco
Sybil Christopher, who has died aged 83, was the injured party in Hollywood's most famous on- and off-screen romance, that between Richard Burton and Elizabeth Taylor during the making of Joe Mankiewicz's blockbuster epic Cleopatra (1963). Sybil Williams, as she was born, was the girl from the Welsh valleys whom Burton had married in 1949. Theirs was a tenacious and loving relationship that survived the actor's affairs with Claire Bloom and Susan Strasberg, among many others, and his hell-raising exploits.
Having ditched her own career as an actor to follow his star – and raise their two daughters – she always remained discreetly quiet about the marriage, filing for divorce in 1963 on the grounds of "abandonment and cruel and inhumane treatment". Moving to New York, she made a new career for herself on a tide of goodwill. She told Time magazine that a woman had come up to her in the Plaza hotel and declared: "We, the women of America, are behind you."
She turned her celebrity by association to good effect and became a nightclub owner and disco queen, marrying a rock singer 13 years her junior, and retiring only last year as artistic director of the Bay Street theatre in Sag Harbor, Long Island, New York, which she had co-founded in 1991.
Petite, silvery-haired (she said she started to "go white" at the age of 12) and vivacious, she relished the memory of herself and Burton as two Welsh kids travelling first-class on the Queen Mary to New York. "In retrospect," she said in 1994, "that is what I would like to preserve, that nice warm feeling I had on the boat. I had the 23-year-old, the best. I look at the pictures, but I don't know that other guy. I had the golden boy."
Williams came from a large family in Tylorstown, Glamorganshire. Her father was a coalmine official, her mother sang in the chapel choir. Both were dead by the time she was 15 and she moved to Northampton in the Midlands to live with her married sister. There, she worked as a window dresser and participated in amateur theatre.
She applied to drama schools in London and was accepted by both Rada and Lamda, but a mix-up in the post led to her not receiving the offer from the first school, so she took a scholarship to the second. In her last term at Lamda, a teacher recommended her to the Welsh writer and director Emlyn Williams, who was filming The Last Days of Dolwyn (1949), which starred Edith Evans as a difficult woman refusing to leave her home in a flooded Welsh valley, and Burton, making his movie debut. Sybil was one of six young extras.
The couple became joyously inseparable – they always called each other "Boot" (as in the Welsh-accented "beautiful") – and married before the film was released. Sybil made her one and only West End appearance, in Mary Chase's Harvey, the play about a man and his imaginary rabbit later filmed with James Stewart, at the Prince of Wales theatre in the same year.
She appeared with Burton in the 1951 Stratford-upon-Avon season – "that wonderful summer," she called it – when he played his coruscating Prince Hal in Henry IV, Part 1; she was Lady Mortimer, speaking only in Welsh, in a company that also included Hugh Griffith, Rachel Roberts and Burton's great friend Robert Hardy. Griffith and Roberts also appeared alongside the Burtons in the famous 1954 BBC radio recording of Dylan Thomas's Under Milk Wood; Sybil played Myfanwy Price, dressmaker and sweetshop-keeper ("I will knit you a wallet of forget-me-not blue, for the money to be comfy. I will warm your heart by the fire so you can slip it under your vest when the shop is closed").
The Burtons had settled in Hampstead, north London, and had two daughters, Kate, who became an actor, and Jessica. But as Burton's career rocketed through his Old Vic Hamlet (with Bloom as Ophelia) and Hollywood, so his behaviour became wilder. The family moved to Switzerland in a bid to keep the domestic show on the road, but the strain was showing.
Sybil did not wholly rally until after the split and the move, with her daughters, to New York. She joined a new project, the New theatre on East 54th Street, and downstairs, in 1965, co-founded the disco Arthur, which rapidly became the hottest nightclub in town (the more famous Studio 54, on the same street, did not open until 1977). A democratic door policy welcomed young professionals as well as the stars – Andy Warhol, Princess Margaret, Truman Capote and Rudolf Nureyev were regulars – and the DJ Terry Noel claimed to have invented in Arthur the practice of "mixing" records using two turntables.
Sybil hired the Wild Ones as the resident rock band, and in 1965 married their lead singer, Jordan Christopher; a daughter, Amy, was born in 1967. She sold the club in 1969, but had by then opened others on a similar model in Los Angeles (where she and Jordan resettled), San Francisco, Dallas and Detroit.
Relocating again to Sag Harbor, where she lived for the rest of her life, Sybil was a founder of the Bay Street theatre in an old warehouse near the town pier. The 299-seat venue began as a summer theatre drawing on the talent of playwrights who lived locally – Joe Pintauro, Terrence McNally and Lanford Wilson– but soon expanded to an all-year operation, attracting actors of the calibre of Ben Gazzara, Mercedes Ruehl, Alec Baldwin, Richard Dreyfuss, Dana Ivey (who appeared in a production of Blithe Spirit with Twiggy) and Sybil's daughter Kate.
Jordan died in 1996. Sybil is survived by her daughters, a stepdaughter and two grandchildren.
• Sybil Christopher, actor and producer, born 27 March 1929; died 9 March 2013