Finch's next three films saw him support notable female stars: Sophia Loren in Judith (1966), Melina Mercouri in 10:30 P.M. Summer (1966) and Julie Christie in Far from the Madding Crowd (1967). He was reunited with Aldrich for The Legend of Lylah Clare (1968). The Red Tent (1970) was an expensive international adventure film, with Finch as Umberto Nobile.
During this time, Finch continued to appear on stage in various productions while under contract to Olivier. Finch's closeness to the Olivier family led to an affair with Olivier's beautiful but increasingly unstable wife, Vivien Leigh, which began in 1948, and continued on and off for several years, ultimately falling apart due to her deteriorating mental condition.
Finch was married three times. In 1943, he married Romanian-born French ballerina Tamara Tchinarova; they worked together on a number of films. They had a daughter, Anita, born in 1950. They divorced in 1959, after she discovered his affair with actress Vivien Leigh in California. He then married South African-born actress Yolande Turner (née Yolande Eileen Turnbull); they had two children together, Samantha and Charles Peter. During their marriage, Finch had an affair with the singer Shirley Bassey. Bassey had a daughter, also named Samantha, born in 1963; Bassey's husband at the time, the openly gay film producer Kenneth Hume, believed that Finch was her biological father. Finch and Turner divorced in 1965. In 1972 Finch married Mavis "Eletha" Barrett, who was known as Eletha Finch. They had a daughter together, Diana.
Finch co-wrote and directed an award-winning short film, The Day (1960) and announced plans to direct a feature but it did not eventuate. He won his third BAFTA for Best Actor for No Love for Johnnie (1961), although like Oscar Wilde, the film lost money. He was originally chosen to play Julius Caesar in Cleopatra (1963) and filmed scenes in London, but when the film was postponed he withdrew; the role was recast with Rex Harrison.