Anastasia Steele: You may call me Mrs. Grey.
Christian Grey: You insist on defying me, Mrs. Grey. What should I do about that?
Anastasia Steele: Learn to live with it.
Christian Grey: Good morning, wife.
Anastasia Steele: Good morning, husband.
Anastasia Steele: I just can't believe this is my life, that I get to live with you.
Christian Grey: I'll pick you up at five.
Anastasia Steele: I may not be done by then.
Answer: He was trying to make her understand how she made him feel whenever she broke a promise (usually about her safety) by punishing her and it became too much, too intense. She also felt like it was revenge instead of love.