White Fire (1976)

Vanessa Johnson has always been a swinger. One man was never enough, not until she met Tim at a swinging orgiastic party at her country retreat. In the midst of sexual excitement they discover each other, and the bliss of a one on one relationship. She becomes a fanatic on fidelity with only one restriction: marriage is not for her. The shock of her life comes when she finds Tim in bed with her secretary, and she returns to her cottage in Maine to be alone and appraise her life, troubled doubt about her lover. The next morning she tries frantically to leave, but the car has broken down and she is snowbound by a storm. Being isolated, her mind begins playing tricks on her. After a complete mental collapse, the paintings in the house become alive in an erotic kaleidoscope as she fantasizes an alter ego that is all things to all men,White Fire consumes her and all those around her. The next morning Tim has come to the cabin, and she believes he is just a fantasy. He convinces her of the truth; nothing has happened with her secretary. A nervous breakdown was imminent, but now with love and help she can recover and they can be happy together. They stroll out into the snow, and Tim plans to take her back into town when the inexplicable happens, leading to this story's shocking climax!