He paced a lot after she left. They would hear him downstairs, mumbling and pacing. His sisters swore that he'd walk through the floor one day, because there was even a dent in his floor. Kon was nearly strangled every time he even started to mention her name. He withdrew, completely, from everyone. Oh, he pretended well, talked to people at school, if they talked to him first, but it was easy to see he wasn't there, for those who knew him well enough. Orihime caught him crying once, at school during lunch. She pretended not to notice and just walked away. It was probably best that way, that he didn't know she saw. He would feel awkward then, and she only wanted to help him. Urahara saw it in his eyes when he came back. A part of him stayed behind with her, the part that she'd changed, made stronger. The part that wasn't part of him before she came, and most of what he was after. Ichigo changed, became isolated, closed himself off.
Then she came back, brought Ichigo with her. He'd smiled, wanted to hold her, but he'd only smiled. How could he tell her? He had no way, no chance, no choice. He was only a human, a substitute Death God. How could she ever love him? Then she told him, one night sitting on his roof, their roof. She'd said "Ichigo, Aishiteru."
He'd cried. She'd gone to him, placed her small hands on his face, asked what she'd done wrong. He simply crushed her lithe body into his with strong arms and told her that she'd done nothing wrong. That he'd waited so long to say two simple words. "Shinigami, Aishiteru. Rukia, Aishiteru."