Julia and Julia (1987) Giulia e Giulia - Sting

Julia, an American woman living in Italy, becomes depressed and traumatized after her husband Paolo is killed in a car accident on their wedding day. Six years later, she inexplicably finds herself sliding between two different worlds: in one she is still struggling with her grief over Paolo's death; in the other she is married to Paolo. In the latter timeline, Paolo is alive and well with their 5-year-old son, and Julia is having an affair with a British gentleman named Daniel. The frequent supernatural sliding between these two worlds threatens to drive Julia crazy, as she has difficulty telling them apart. Then she learns which world she currently inhabits.