Help with Questions to Scarlet Pimpernel: Chapter 16

Chapter 16
How has Marguerite’s choice changed her? (125-6)
How has Marguerite’s opinion of Sir Percy changed? (125)
Why didn’t Marguerite explain the St. Cyr incident to Sir Percy previously?
Why does she explain it now?
What does Sir Percy think of his wife?
Why does Sir Percy hid his feelings for his wife?