Sudden realization

None of what Ma Yuan saw made any sense to him. If his wife detected the intruder before she stepped into their house, why didn't she trigger the formation array? Even if it didn't work, it may have bought them enough time to run away together.

Also, there was the matter of the seal. All this time he thought it was the intruding lady who did something to him that made him unable to remember her face, but it turned out, it was his wife.

Why didn't she want him to remember the face of the perpetrator who split their family apart? 

Why did it seem like she gave in way too easily almost as if she was capitulating to the enemy?

However, he pushed all these doubts and questions to the back of his mind as he focused on his true goal, the rest he could mull over with time or ask his wife if they had the good luck of reuniting, but for now, his sole focus was the lady in the white robe.