Here's the second part told in Robin's perspective:
He never expected leaving her to hurt so badly. He certainly didn't expect such a calm reaction from her when he told her of his decision. He expects crying, pleading but as always she surprises him. She just accepts it wishing him the best. Treating him as a casual friend instead of the man she was to marry.
He wonders if she realizes all she would have to do is ask, show some sign that she wants and needs him and he would have stayed. He loved her too much even then to deny her anything. Not that they ever talked about their feelings then. It isn't until years later when both of them faced constant death that they become comfortable with how vulnerable they make each other and start being honest about their feelings.
She acts nonchalantly then as if he doesn't mean a thing to her. There are so many things he wishes he could say to her but the words lodge in his throat. He calmly rides away from her not showing how it is breaking his heart. He has a fleeting thought that he is making a mistake but dismisses it. Later he will curse her for making it so easy to leave.
He expects glory and noble deeds. The truth is so far removed from what he imagined.
The night after his first battle he breaks down looking up to the stars which are different here. He feels so isolated here and misses her intensely not feeling whole without her. He wants nothing more than to go home. He dreams of her and doesn't know if they help or make the days more difficult.
Five years he spends in that hell. He went to become man worthy of her. He has to laugh at his naivety. War doesn't make men just shells of them. He doesn't think he'll ever wash the blood off his hands or cleanse the sand from his lungs.
He is happy when he gets wounded for it means he can return home to her. Nothing is the same he finds. He laughs bitterly at the irony of it all: he is home, she is unmarried but she seems further away than ever.
There are so many words that need to be spoken between them: I love you, I need you, leaving you was the worst mistake I ever or will ever make, I'll never leave you again. Fear prevents him from speaking. He couldn't stand to know that she doesn't love him.He stays silent until it is almost too late and finds to his surprise that she forgives him and does love him.
Still it isn't easy. They have all too brief stolen moments. It shatters him every time they part. He is only put back together again when she is back in his arms. He wonders if she realizes she is the reason behind everything he does or how much he needs her.
Later when they are finally able to be together he thanks the heavens for her everyday. He knows he doesn't deserve her. Everytime he sees her smile at him or watches her with their children or holds her he realizes that hell was worth it. It took a war and believing he had lost her to make him realize just how desperately he loves her. To make him see how rare and precious what they have is and he spends everyday the rest of his life showing her just how much she means to him.