It's funny but that mirror thing is how I've tried to lose weight in the past - and it never worked. This though is different.
I realised that, as you say in your second sentence, she doesn't love me for what I look like. What I discovered was that the feeling of being ashamed was actually a projection of how I felt about myself. I was doubting her love for me based on nothing that she had said or done, but rather on the words of rather unkind people over the years. I was actually being rather unkind.
So no, I'm not doing it
for her, but I am doing
thanks to her because it was her accepting me as a fatty that gave me the confidence to go through with it. My thinking partly being "if she finds me this attractive as a fatty, imagine the look on her face when she sees me without all the padding".
Mainly though my thinking is that you only get one go at this life and I'm not going to zimmer my way into heaven. If I'm going to heaven I'm going to crash through those gates looking fantastic, backwards, in a fast car and on fire.
So this is my wedding present to me.