Zuko leaves Mai a letter.
Part 4 - Mirrors - Shard 9/11 - The Letter
Dear Mai,
I'm sorry you had to find out this way but I'm leaving. By the time you get this, I'll be gone and labeled a traitor to crown and country. The months I've gotten to spend with you were sweet and eye-opening. For the longest time, I believed my scar meant I would never get to experience any semblance of love. So I buried everything and refused to allow myself to feel for anyone. But during the siege of Ba Sing Se, I was taught that I get to decide if my scar defines me. Then you came along and showed me what that love could be like. For that, you will always have my gratitude and a piece of my heart but I am not the person who you think I am. That place I fought for and tried to fill, I will never be that person Mai. My father said I had changed and he was right, I need to stop resisting that change and do what is right.
I'm sorry for leaving and I am even more sorry to end things like this but I cannot risk bringing you into what I am about to do. I will not have your name tarnished because of my mistakes. Contrary to what everyone was told and despite my best efforts, the Avatar lives.
All this time I have been angry at myself because somewhere I have known that I am supposed to help him. Instead, I betrayed the only person aside from Uncle who believed I had some good in me, and in turn, I almost caused the Avatar's death.
Uncle has told me numerous times, my destiny is intertwined with theirs, I have just been too stubborn to listen and it has cost him dearly. I have hurt so many in the last few months including you. I am going to face my father, find my uncle and join the Avatar. Hopefully, I can make up for my past actions, atone for the Fire Nation's sins and help bring peace and kindness back to this world.
I do not know if I will be successful, Agni I don't even know if I will survive this. I do know that, while I was not the best, I loved you with all of my heart but I need to let you go. I hope that one day you are able to forgive me and that you can find a love that is worthier than I. One that is worthy of a person that is as loving, strong, and steadfast as you.
With the last embers in my heart,
Zuko
As much as Zuko can be grumpy and broody he has a soft side and you could see that with his interactions with Mai. Granted I always thought Mai would be much happier with a certain someone else and I hope to get them together at some point in this fic :)