Deceptions (1985)

Stephanie and Sabrina are twin sisters. Stephanie is a housewife, who doesn't seem content with her life, while Sabrina is a jetsetter who lives in London. They go to Venice for their birthday and they decide to see how the other's life is. So Sabrina goes to Stephanie's home and becomes mother to her children and wife to her husband Grant. Problem is that Stephanie is a little insecure of an attractive student who is always flaunting herself at Grant. While Stephanie enjoys Sarina's life until her sadistic boyfriend comes into the picture.