Madaline herself has been deceived.

I told her that you knew all her history, that I had kept nothing from you, and that you loved her in spite of it, but that she was never to mention it to you." He read the letter with a burning flush on his face, which afterward grew white as with the pallor of death; a red mist was before his eyes, the sound of surging waters in his ears, his heart beat loud and fast.
Could it be true--oh, merciful Heaven, could it be true?
At first he had a wild hope that it was a cruel jest that Philippa was playing with him on his wedding-day.

It could not be true--his whole soul rose in rebellion against it.

Heaven was too just, too merciful--it could not be.

It was a jest.