Complex sentence: In 1975 he married Gundula Ahl, with whom he had three children, one of whom is composer Wieland Hoban, to whom "Riddley Walker" is dedicated.
Split into simpler sentences: In 1975 he married Gundula Ahl, with whom he had three children. One of his children with Ahl is composer Wieland Hoban, to whom "Riddley Walker" is dedicated.