Leave the past in the past. Honestly, if your relationship is good... why ruin it with these thoughts constantly running through your mind?
But I feel you man, I've always had the "history" talk with my past girlfriends and my current one. It honestly does nothing to help the relationship... just pounds your thoughts from time to time. You can't change whats done, just be happy you have her now.
embrace this moment
we are eternal
all this pain is an illusion