They say the hardest part of a tree's trunk is where a wound has healed over.
Everyone has been through something like this, right? Lying awake at night, unable to fall asleep, while all kinds of images play through your mind. The person you used to be, the person I used to be, the people we used to be, through joy and sorrow, worry and pain. Many people can't stay by your side forever just because you want them to. Many things won't go the way you want, no matter how much you wish they would. There's nothing you can do. Time changes everything, and people and things are never the same. Those can all be good enough reasons.
If you don't have the courage to bear betrayal, don't dream of staying together until death.