Kimimaro ran his hands through his hair, staring silently at the ground. It had been many years since Orochimaru had chosen Sauske as his protégé. He hadn't thought of it as abandonment, after all, he was very near death from sickness. But the Konoha medics who'd found him after their fight had saved his life and, with the help of their hokage, his illness nearly cured. He would never be fully healthy but his life wouldn't succumb to the illness that had controlled him for so long. As the days went on, he realized how little he had once valued his own life and how important he felt he was now.
However, that didn't stop the jealousy he felt towards Sasuke, his replacement. The combination of the curse mark and his kekkei genkai had been so desirable before Sauske. Once Orochimaru had set his eyes on the Uchiha child, everything was focused on only him. Kimimaro's rage was so strong that he was afraid he'd act upon it.
Years passed and his jealousy lingered. He relied on his other interests to distract him, teaching the young students he loved. He wouldn't let what happened to him ever happen to them. Every student deserved a good life and that included Sauske's daughter, despite his relationship with her father.
He watched him drop her off everyday and as he saw the person he had become, his jealousy lessened slowly. The process was slow but, eventually, he was able to speak with Sauske without the burning sensation of jealousy burning in his heart.