A Change of Seasons (1980)

A self-centered university lecturer thinks it's quite all right that he has taken one of his students as a lover, but is deeply hurt when his wife retaliates by taking a similar approach with a visiting carpenter. His announcement that he is off to the family holiday home for some skiing with his paramour is met by his wife insisting she and her young joiner go too, and the four set off for an awkward time in the snow.