In the past, Spock had never been stopped. Sure, they tried, but Sarek didn't want to bring attention to his household for his son being too human. Amanda tried, but she didn't know how to deal with a child that was too Vulcan.
Naturally, Vulcan researchers had been interested in his existence since his conception due to the odds of it all. Doctors suggested that his mother abort him, citing the prognosis of an eventual miscarriage. Amanda, who had given up hope of having a child of her own blood, stubbornly refused to do so. No one thought that he would be born alive, but alas, he was.
They were interested in the combination of his parents, the hybridization of the species that he exhibited. His ears were Vulcan. His eyes were human. His blood was Vulcan. His genitalia, however, confused them all. Instead of being able to clearly see which species' trait was dominant, it was apparent that it was codominant. He had the penal sheath of a male Vulcan but the uterus of a female human. Unsure of what sex to put him as on his birth certificate, the doctors simply labeled him as neutral.
He had been raised a male by his family however, who deemed it logical that they go off of the Vulcan characteristic due to their household in Shi'Kahr. They had both been hesitant and unsure, but Amanda stressed that the other children would use every oddity about him in hatred during his school years.
That was when it all started. Before school, it had just been Amanda, Sarek, Sybok, and Spock. None of them were outright cruel to the half-Vulcan despite his parents' disagreements on how he should be raised. Even Sybok respected him, but he himself went against most Surakian principles. When he went to school, he was finally exposed to the horrific bullying that his mother had been afraid of. They called his father a 'traitor' and his mother a 'whore.' He was called a 'freak' and a 'hybrid' and every synonym of those two words in the dictionary.
That was when he first took to the knife. He had done his best to put up crude shields against his family, not that they were around to stop him at the time. Amanda and Sarek had been away, and Sybok had already left the family in dishonor for good.
If his parents had noticed his raised shields during his childhood, they certainly never questioned it. Green blood would spill on his thighs over and over again whenever Spock had problems regarding his place in the world. Doctors couldn't specify a species, couldn't specify a sex...
Spock had run into Sybok once with blood staining his clothing. He was horrified, terrified for his brother, and his emotions violently raged. Then, he disappeared.
Amanda had soon after found out too, leading to Sarek learning of it. She cried, saying she knew something like that might happen. Apparently, she had seen it in his eyes. She had read up on depression and anxiety, but none of the advice she had recieved had been useful to either of them.
Then, Michael came. Spock didn't like her at first, which was obviously illogical. He taught himself that lesson on his thighs once more. She was human, of course she required more affection from Amanda. He wasn't human enough to get that from her. As always, he was too Vulcan.
He made sure to stay at the top of his year, not wanting to face the fierce tongues that would abuse him if he fell behind. They still found him though. They always did.
Stonn hated him the most. Spock was never sure why, but he most have had some logical reason. Maybe it was because he had always like T'Pring, but she and Spock had been set up with each other.
Michael found out about his habit right before she left for Starfleet Academy and had been ready to stay and help him deal with it together. Spock had refused, citing that it was useless for his malaties to burden others as well. She left reluctantly.
Then, there was no one left who understood him in the slightest. While he hadn't liked her at first, she became valuable to him as another person who was too human for the other Vulcans. Green blood was spilled when she left.
Every defining moment in his life was sprinkled with a spray of blood. Every illogical action like turning down the Vulcan Science Academy had defined him.
When he followed his sister to Starfleet, he had been too Vulcan there. It was fairly obvious that not a lot of Vulcans went there, and the humans loved to pull punches with their words and their fists.
When Pike took him under his wing, he had already known about the issue. Spock had always suspected that that was one of the reasons he was selected. The man had been rather good at keeping him from harming himself, a lot better than his family had been. Knifes were few and far between, and it took longer for him to get a phaser than it normally should have. In the end, he could not quell the Vulcan's need for the painful bliss.
When he got with Nyota, she had been horrified to learn of it. She tried to help him every day, treated him as more of an equal than others had. He hadn't been too Vulcan for her, but all the same, others' views clouded his mind.
He couldn't show emotion or feel anything. If he did, he had to reeducate himself. He couldn't make illogical decisions and would reeducate himself if he did.
Spock cut himself when he cast off Kirk go Delta Vega. He had cut himself when he failed to save his mother and his planet. He had cut himself when they broke the prime directive and after he learned from Jim that he shouldn't have reported it. Whether it was due to his emotions or his confusing body structure, no one could stop him in the end.