Rent Butterflies: Series 1 (1978)

Ria is a seemingly happily married mother of two teenage sons. Her husband is the lugubrious dentist Ben. His hobby is collecting butterflies, although he seems to spend most of his time arguing with their sons: the thoughtful Russell and the ever cynical Adam. After 19 years of marriage Ria believes that everyone is taking her for granted and yearns for just a little excitement. Then one day she bumps into a handsome businessman Leonard, whom she dreams will sweep her off her feet.