The Conqueror's Queen by Monica Vale

When Matilda of Flanders refuses to marry William of Normandy, he responds by storming into her father’s palace to whip her bare bottom with his strap. To the world’s amazement, she reacts by accepting his proposal. Why would she agree to marry a man who had treated her so brutally?

To the modern reader, the answer seems very clear: she secretly enjoyed submitting to his punishment, just as he enjoyed inflicting it, and they did their best to hide her feelings from the world. But what will happen to them when their son learns their shocking secret, and she is forced to choose between her husband and their child?