Looking for a story where a lord is getting married and essentially swaps wives with his servant for practice

[retrom]

I've been looking for this story actively through every method possible.
It's essentially about some sort of lord who is getting married to a young bride. He has trouble performing and his servant's wife helps him 'practice'. Similarly his servant is asked to help pleasure his bride. It's a sweet story and both women end up pregnant at the end.
Thanks all!