Records of annulment of German nationality show Ludwig living in Berlin with Else geb. Goldschmidt born in Thorn in 1895, and children Lotte born in Stettin in 1911, and Hans-Guenther born there in 1924. I assume that Lotte and Hans-Guenther are Ludwig's children by Gertrud and Else respectively. What became of Getrud is not known. See also ancestry.com.