At times he felt it building itself inside of him, the remnant of his mother's horrific death that stuck inside of him, compelling his need. With every kill, every sickeningly sweet scream from the latest monster he found on his table, he felt closer to her.
An event so pathologically sick it had effectively destroyed his capacity for feeling, but a part of him knew his emotions were still in there. He could feel them wriggling in him, squirming in distaste with every kill. Yet, he killed anyway, because feeling that pain, feeling anything, was better than the emptiness that otherwise consumed him.
He almost stops, he really does, when he realizes he loves Rita. It's a strangely sweet feeling, it feels good and he's not used to it. He's almost put off by it, but he starts to understand his capacity for positive emotion. It is then that he makes up his mind to give up killing. He has another path, now.
But Rita dies, and he's left with the horrific scene of his son, sitting in a pool of his Rita's blood as Trinity mocks him from the grave. "Born in blood," he thinks to himself, taking in the gruesome sight, "just like me."
He desperately latches on to anything he can, trying to feel that same emotion he had for Rita. but it's gone, refusing to come out. His light side had been hurt too much, too many times to ever show itself again.
But it does, eventually. To some extent with Hannah, but more than he's willing to admit with Deb. A part of him, really, most all of him at this point, is resentful of his past, his compulsion to kill. A part of him had died when Debra told him she had been in love with him, past tense. Another part dies when she swerves, sending them both into the water.
But his capacity to love just grows stronger all the while. Once again, he resolves to give up killing, to run away with Hannah and Harrison and finally have a family.
But then Debra dies, and just like that it's gone. He still has Hannah, but without Deb he feels nothing for her. Finally he makes up his mind. Debra goes in the ocean, and so does he. And when he survives, he sighs a heavy sigh and silently screams, before his emotions leave him once again.
Back to repression it is.