Doubtful Twosome "Yuu and Satoshi Are a Couple?!"
Miki and her friends are grieving over the fact the the marathon tournament is coming up. Then they heard a rumor that Yuu and Satoshi are a couple at school. So Miki and Meiko go to spy on them. They like a good couple. How does Miki react to this?
Aired 24/07/1994EP 20 - Doubtful Twosome "Yuu and Satoshi Are a Couple?!"

Marmalade Boy
Miki Koishikawa lived a normal life - until her parents tell her they'll get divorced.. She doesn't agree, until she meets Yuu Matsuura... the handsome son of another couple, with whom her parents are switching spouses. They all live together now in an enormous house, and Miki and Yuu find themselves falling in love. They'll have to struggle with their own feelings, other people who want to be with them, and whatever Lady Luck and Fate throws in their ways...
(Source: Anime News Network)