Degrassi Junior High (1987)

S3E13 Making Whoopee

Arthur is not fond of his dad's new girlfriend, so he teams up with Yick to try and split them up. When his schemes fail, he's taken aback to discover that his dad's girlfriend stayed over. At the school open house, Arthur is outraged when his father arrives with her in tow. However, he feels guilty when his dad later confides that he has ended the relationship.