My fiance has no idea that I almost left him for his childhood friend.
What made you stay with him instead of moving on?
I realized that I couldn't live without him.
It is good that you didn't leave him in the end, your relationship has so much history than you and the childhood friend ever did. I hope you never told him about this, because he will be devastated about your potential betrayal.
True I never told him about it. He's happy that I decided to marry him.
I hope you're happy as well, it seems like you made the right choice.