Racing car driver Mark Loring, the heir to the Loring fortune complements his competitive spirit with jealousy of his wife Mary. Enraged by the attention shown to her by a "fan" during an evening at a restaurant, the couple is greeted by longtime friends of Mark's family, who invites them to join them at their table. Mark declines, but relents by saying, "just one drink".
After divulging to Mary that Mark's mother was a singer who walked out on the family when Mark "was a baby", Mrs. Duncan's asks Mary (who, too, was a singer), to sing a favorite old song. Mark tells Mary not to, and that he "won't have it", but she defies Mark and does. Miffed, Mark purposely does not light Mary's cigarette, upon which she retaliates by leaning over exposing her cleavage to Mr Duncan, who delightedly obliges.
Seconds later, Mary runs to the beach and Mark follows. He asks her what the devil is she trying to do to him, and proceeds to make angry and fiery love to her. After reconciliation from the night before, Mark, once again becomes jealous when Mary receives a call from her "fan" who wants to return her dropped glove form the previous day's race. Mark pouts, that he "doesn't care to share her, he never seems to have her to himself, and there's always something--somebody". With that, Mark decides to whisk American Mary away home, to London.
During their drive, Mary tells Mark that she is going to have baby, and Mark replies, "ours, I hope". Mary slaps Mark and they get into an accident. While recovering in separate rooms, Mark's father tells him that Mary lost their unborn child; the doctor informs Mary that Mark is sterile. When the couple comes together, they console each other, however, Mark is unaware of his condition. Mark's father anticipates and hopes the "affair" will end, and attempts to buy Mary off. But she holds firm and tells Sir John she's not for sale, that she and her husband needs to be alone, and what Mark doesn't know is that his father is the enemy.
Mary learns that Mark's father later reveled that he was sterile when Mary tells Mark she wants a baby. She comes up with the idea of artificial insemination and attempts to resolve their difficulties by travelling with Mark to a clinic in Switzerland. Soon pregnant, and though Mark had initially agreed, he becomes alienated from the idea when he thinks Mary is having an affair with a local skier who helps Mary to his cabin when she injures her ankle on the ski slopes.
Returning to London alone, Mark and his father Sir John Loring take Mary to court for divorce on the charge of artificial insemination being a case of adultery. Undeterred, Mary decides to fight to preserve the reputation of her unborn child, and to confirm why another child would bring the two closer together; she only wanted her husband love—although the prosecution cried material benefit to Mrs. Lording.
During proceedings Mary's attorney encouraged her to continue when she wanted to quit. He needed her permission to re-examine her husband's character (jealousy). Upon cross, Mark's personality was brought into cler view; establishing that he didn't like Mary being civil, accepting a light from a friend, singing in a nightclub or offers of hospitality when there was no other alternative. It was established that Mark was jealous from the very outset of the marriage and that the divorce proceedings were motivated purely and simply by his unreasonable and uncontrollable jealousy.
Mark was also reminded that he made a spectacle of his wife during the Iberian Gran Prix, when, at the Hotel Playa, he forced himself on his wife while other eyes were watching from a terrace overlooking the public beach—even though he was aware, yet his wife unwilling. Mark's actions were further put on trial when it was noted that he told his wife he would "make up" their loss of the baby, that he signed a document agreeing to wife's treatment of artificial insemination—but later changed his mind (without saying so), and he made love to her after she first told him she was pregnant. This proved he condoned and accepted her "condition".
Sir John was also cross examined about his feelings and objections (similar to those he felt of his former wife) toward his son's show-biz, theater, singer wife. And it was uncovered that a bribe was offered. Sir John claimed he was protecting his son by informing him of his sterility, his passing infatuation with his wife, and the protection of the Loring Estate. In deep contemplation after the senior Loring's testimony, Mark exited the coutroom for a cigarette without a word to his father.
Dr. Cameron's was next to defend his position. The prosecution's claim of "technical adultery" by artificial insemination was struck down as not being adultery at all. Producing a baby "artificially" via "test tube" and not another via intercourse was not the same as adultery. Moreover, the definition of adultery also negated the very act of which Mary was accused.
In the end, Mark stands up to his father, finally realizing he's made a mess of his marriage and recognizes his father as the controlling figure who plays God. He walks out telling his father there will be no more dinners. Back at court, Dieter offers his assistance to Mary, if ever in need. Mark and Mary meet while waiting the decision and tells her, he will always love her.
The verdict could not be read, as the jurors could never agree. Mark refuses a retrial and says he was completely wrong and should never "have brought it". Through his attorney, Mark begs the court's indulgence, apologizes for the trouble he has caused, withdrawals the charges, and ask the judge to dismiss the petition.
The response: "I find this an imminently most satisfactory ending".Closing shot with Mark waiting for and receiving her as they walk together with "Strange Affair" playing in the background.Julie London as Mary Loring
Anthony Steel as Mark Loring
Basil Sydney as Sir John Loring
Donald Houston as Mr. Jacobus
Anton Diffring as Carl Dieter
Andrew Cruickshank as Dr. Cameron
Frank Thring as Mr. Stanley
Conrad Phillips as Mario
Kynaston Reeves as Judge
Mary Mackenzie as Nurse Parsons
Georgina Cookson as Mrs. Duncan
Richard Caldicot as Mr. Duncan
John Rae as Jury Foreman
My Strange Affair
music and lyrics by Bobby Troup
sung by Julie London