The Pamela Principle.

Pamela is a young actress who has moved into New York City from the midwest. She meets up with Carl who is middle-aged tailor of women's clothings and is going through a "mid-life crisis". He sees his son's amourous escapades and longs for better relationship with his wife Anne who is distant at times. He has an affair with Pamela. But Pamela's lifestyle does not go well with him.