Looking for a story

I am trying to find a story I have not read in many years. I don’t remember where I found it.

It was about a husband and wife, who were sailing around the world. They stop on an island, do a good deed, meet an old woman, who offers them both a wish. They wish for each others happiness.

They continue on their way, and slowly swap genders.

Ring any bells?

Kristine (Roland) Read