Leon never understood why you were married to his brother. Yes you didn't married him by choice but to stop the Water-Fire Nations war but still. Even years after the war stopped you were still there even though his brother cheated on you constantly.

That's why he offered to be your bodyguard when he noticed how lonely you looked and soon he fell for your charms.

"Just divorce him. I'll treat you better." Leon mumbles as he follows you to your chambers after a meeting with the Council.