When the Romans left Britain, various groups of people started infighting over supremacy on the islands. The anglo-saxons used this to completely conquer the land which was an easy job for them considering how advanced their warriors were compared to the locals. Normans actually ended anglo-saxon rule much later. Credit to Greenleafable for this answer and explanation btw.
Explanation:if he had been a good and responsible father, he wouldn’t have cheated and would have thought about the children and how it would affect them before taking action