Hello, here is the archivar from german Church Liverpool, Ilona Ziessler. I could found out for you:
John Simpson , Stewart Marine, 32 years old, from Aberdeen married Katharina Elisabeth Roennebeck, 27 years old, maid,from Vollerwiek near Tetenbuell in Schleswig-Holstein, the northest part of Germany.
They married 04. December 1882. Widness of the wedding: James Rogiar, William Haggarty, Lizzie Mc Vee, Margeruite Vaughan.
The father of John was Robert Simpson, stonemason.
Father of Elisabeth was Peter Andreas Roennebeck, a farmer.
(entry number 87 in the German Church Liverpool, marriages record)
I found one child:
28. August 1884 Martha Magdalena
the family lived in Liverpool, 65 Tiber Street
widness: Martha Trietschel
Hope it hepls,
best Ilona
0151-48651